KSEEB Class 10 Science Important Questions Chapter 8 How do Organisms Reproduce?

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Karnataka SSLC Class 10 Science Important Questions Chapter 8 How do Organisms Reproduce?

Question 1.
Define reproduction.
Answer:
The biological process by which organisms produce young ones, which resemble themselves, is known as reproduction.

Question 2.
Explain the importance of reproduction in organisms.
Answer:
Reproduction is an important characteristic feature of living organisms. It is an essential life process, which not only helps in survival of the species but also helps in continuity of that race and group. Young ones replace the old and dying ones. These young ones feed, grow and reproduce again.

Reproduction also helps in increasing the population of the species. Reproduction acts as a vehicle of organic evolution by transmitting advantageous variations to the offspring. In the absence of reproduction, species would perish and life on earth would be wiped out of existence.

Question 3.
How are the modes for reproduction different in unicellular and multicellular organisms?
Answer:
Unicellular organisms generally reproduce asexually by fission, budding or spore formation. Their body has just one cell, which can easily multiply by simple cell division, budding or spore formation.

Such methods are difficult in multicellular organisms as they have a complex organization of specialized tissues. Therefore, multicellular organisms usually reproduce by sexual method.

Question 4.
How does reproduction help in providing stability to populations of species?
Answer:
Population of any species will remain stable when the birth rate is equal to the death rate. Reproduction produces new individuals, which will compensate for the deaths. Thus reproduction provides stability to population of a given species.

Question 5.
Is reproduction essential for the survival of the individual?
Answer:
No, reproduction is not essential for the survival of the individual. An organism incapable of reproduction will also survive and complete its life cycle. However, reproduction is most essential for the growth in population and survival of the species. In the absence of reproduction, species will be wiped out of existence.

Question 6.
Why do organisms of the same species look similar?
Answer:
Reproducing organisms create new individuals similar to themselves. The individuals of the same species are the products that emerge from a common but similar blueprint. The DNA of the parents decides the blueprint. During reproduction, similar copies of the blueprint are produced by a process called DNA copying or DNA replication.

Question 7.
What is variation? Why are hereditary variations important?
Answer:
The young ones of any species may resemble their parents broadly but differ from them in many ways. The differences in the characters among the offspring compared to their parents is called variation. Variation is necessary for organic evolution.

Question 8.
What is DNA? What is its structure called? Where is it located in the cell?
Answer:
DNA stands for Deoxyribo Nucleic Acid. It is a macromolecule found in chromosomes of living beings and carries the genetic information of the organism. The structure of DNA is called ‘double helix’ structure.

Every eukaryotic cell has a nucleus, which contains chromosomes. These chromosomes carry information for the inheritance of characteristics from the parents to their offspring in the form of DNA molecules.

Question 9.
What is meant by DNA copying? What is its importance?
Answer:
The process of producing two identical copies of one original DNA molecule is called DNA copying. It is also called DNA replication. DNA replication is important because replication is needed during cell division. Replication allows the cell to be duplicated so that it can continue the process of cell division.

DNA copying enables organisms to beget young ones similar to their own kind. The process of DNA copying brings some variation each time. The surviving cells are similar to but subtly different from each other. This inbuilt tendency for variation during reproduction brings variations among individuals of the same species. This is useful for ensuring survival of the species.

Question 10.
Why is DNA copying an essential part of the process of reproduction?

OR

What is the importance of DNA copying in reproduction?

Answer:
The process of reproduction produces offspring similar to the parents. The exact blueprint of the body is inherited by the offspring due to DNA copying in the parent cell. This is why DNA copying is an essential part of reproduction.

Question 11.
Briefly describe the process of DNA copying.
Answer:
The replication of DNA occurs in every cell during cell division. The process requires the uncoiling of the two strands of the DNA helix. The two open strands serve as templates for the assembly of daughter strands. The assembly of new strands takes place in a complimentary mode.

This process is accompanied by the creation of an additional cellular apparatus. Then, the two DNA copies separate out each having its own cellular apparatus. Effectively, a cell divides to give rise to two cells.

Question 12.
Why is variation beneficial to the species but not necessarily for the individual?
Answer:
Populations of organisms reside in well-defined places or niches in the ecosystem. However, habitats or niches can change because of reasons beyond the control of the organisms. Variations allow organisms to exist in diverse habitats or niches. In the absence of variations, a species may be restricted to a particular area.

If this area gets drastically altered, due to various natural or human-made causes, the species may be wiped out. However, if some variations were present in a few individuals, they could colonize other habitats, reproduce and could survive. But if variations were present in a single organism there would be very little chance for it to survive. Therefore, variation is beneficial to the species but not necessarily for the individual.

Question 13.
Mention the major modes of reproduction seen in animals.
Answer:
Reproduction in animals takes place principally by two modes. They are asexual reproduction and sexual reproduction.

Question 14.
What is asexual reproduction?
Answer:
A type of reproduction in which the young one arises from a single parent and is genetically identical to the parent is called asexual reproduction. This process does not involve the fusion of gametes.

Question 15.
Give examples of animals that reproduce by asexual method.
Answer:
Lower order organisms like amoeba, yeast and hydra reproduce by asexual method.

Question 16.
What is the method of reproduction in amoeba?
Answer:
Amoeba is a unicellular organism. It reproduces asexually by the method of binary fission.

Question 17.
What is binary fission in reproduction? Name an organism that reproduces by this method.
Answer:
A kind of asexual reproduction in which a unicellular parent cell divides itself into two daughter cells is known as binary fission. Amoeba reproduces by binary fission.

question 18.
Explain the process of reproduction in amoeba.
Answer:

Amoeba is a unicellular eukaryotic organism. Its body is made of a single cell. It reproduces asexually by the method of binary fission. The adult amoeba becomes ready for binary fission. First the nucleus divides into two. A constriction develops dividing the cytoplasm into two parts.

The parent cell breaks at the point of constriction resulting in two daughter amoebae, which are identical to that of the parent. This is a form of asexual reproduction called binary fission.

Question 19.
What is multiple fission in reproduction? When does amoeba reproduce by multiple fission?
Answer:
A type of asexual reproduction in which a unicellular organism divides itself into three or more daughter cells that are identical to the parent organism is called multiple fission. Amoeba reproduces by the method of multiple fission under unfavourable or drought conditions to increase the chances of survival of daughter cells.

Question 20.
How does binary fission differ from multiple fission?
Answer:
Binary fission is a mode of asexual reproduction in which a unicellular parent organism divides itself into two daughter organisms through the process of cell division. This method produces two young ones. This happens under favourable conditions in the absence of any stress.

Multiple fission is a mode of asexual reproduction in which a unicellular parent organism undergoes cell division to produce more than two (many) young ones. This type of reproduction occurs under unfavourable or stressful conditions.

Question 21.
Explain binary fission in Leishmania.
Answer:
In Leishmania, binary fission occurs in a definite orientation in relation to flagella. Splitting of parent cell during fission takes place in a definite plane (longitudinally) with respect to flagellum at its ends.

Question 22.
Name the disease caused-by Leishmania.
Answer:
The disease kala-azar is caused by Leishmania.

Question 23.
What is the difference between binary fission in amoeba and leishmania?
Answer:
In amoeba, the splitting of the two cells during division can take place in any plane. Binary fission in Leishmania happens in a longitudinal plane.

Question 24.
What is the mode of reproduction in yeast? Explain briefly.
Answer:
Yeast reproduces asexually by a process known as budding. The parent yeast cell forms a small bud on its own body, which eventually develops into a new individual. On maturity, the bud breaks away from the parent body and gets independent existence.

Question 25.
Describe a simple activity to show the reproduction in yeast cells.
Answer:
Yeasts reproduce asexually by budding. This can be observed under a powerful microscope. Dissolve about 10 g of sugar in 100 mL of water. Take 20 mL of this solution in a test tube and add a pinch of yeast granules to it. Put a cotton plug on the mouth of the test tube and keep it in a warm place.

After 1 or 2 hours, put a small drop of yeast culture from the test tube on a slide and cover it with a cover slip. Observe the slide under a microscope. Now we see many yeast cells and some of them show budding on the outside wall of their cell wall.

Question 26.
How do fungi reproduce?
Answer:
Fungi reproduce asexually by the method of spore formation. Spore formation is a method of asexual reproduction in which the parent plant produces hundreds of tiny spores, which can grow into new organisms under favourable conditions.

Question 27.
Describe how growth of fungus on a piece of moist slice of bread takes place.
Answer:
Take a slice of moistened bread. Keep it on a plate in a cool, moist and dark place. Observe the surface of the slice with a magnifying glass for over a week. A white cottony mass appears on the surface of the bread which gradually turns black. This is due to the growth of bread mould (a fungus). The spores of fungus will always be hanging in air.

They settle on the moist bread which provides favourable conditions for their germination. The cottony growth on the bread is a mass of vegetative filaments of the fungus. These filaments develop asexual sporangia which are black in colour. This is why the cottony mass turns black after a couple of days.

Question 28.
How will an organism be benefited if it reproduces through spores?
Answer:
The following are some benefits for the organism that reproduces through spore formation:

• Reproduction through spores is simple as well as faster.
• The spores are light in weight, thus keep floating in the air. This helps in their dispersal.
• The spores are covered with a thick layer, which enables them to remain dormant in unfavourable conditions.

Question 29.
What is fragmentation? Name an organism that reproduces by this method.
Answer:
Fragmentation is a form of asexual reproduction wherein a parent organism breaks into fragments and each fragment is capable of growing independently into a new organism. Spirogyra is a filamentous alga. It reproduces by the method of fragmentation.

Question 30.
Why do most of the multicellular organisms need more complex methods of reproduction?
Answer:
Multicellular organisms cannot simply divide cell-by-cell or regenerate from its fragments. This is because, many multicellular organisms are not simply a random collection of cells. They have many different specialised cells, which are organised into tissues, and tissues are organised into organs designed to carry out varied but different activities.

These organs are placed at definite positions in their body. In such a carefully organised situation, cell-by-cell division or regeneration of fragments would be impractical. Therefore, multicellular organisms need to use more complex ways of reproduction.

Question 31.
What is regeneration? Name an organism that reproduces by this method.
Answer:
Regeneration is a type of asexual reproduction in which the organism has the ability to give rise to new individual organisms from their body parts. This method of asexual reproduction is found in animals like planaria, earthworm, starfish etc.

Question 32.
With the help of a suitable diagram explain asexual reproduction in planaria.
Answer:

Planaria reproduces asexually by the method of regeneration. In this mode of reproduction, planaria simply constricts its body until it actually separates into two parts. One part is the anterior end and the other is the posterior end. Each of the parts then regenerates the missing portion and thus two complete individuals arise.

Even if planaria is cut into a number of pieces, each piece grows into a complete organism by regeneration. Specialised cells carry out regeneration. These cells proliferate and make large numbers of cells. From this mass of cells, different cells undergo changes to become various cell types and tissues. These changes take place in an organised sequence.

Question 33.
Differentiate between regeneration and fragmentation.
Answer:
Regeneration:

1. This type of reproduction is seen in fully differentiated organisms.
2. It is carried out by specialized cells.
3. Specialized cells proliferate to form a mass of cells from which various cell types and tissues emerge.

Fragmentation:

1. This type of reproduction is seen in organisms with simple body organization.
2. No specialized cells are involved in this process.
3. The parent body breaks into segments and each segment develops into a new organism

Question 34.
With the help of a suitable diagram explain the method of reproduction in hydra.

Answer:
Hydra is a multicellular organism. It reproduces asexually by the method of budding. First, a small outgrowth called ‘bud’ is formed on the side of its body by the repeated mitotic divisions of its regenerative cells.

The bud grows gradually to form a small hydra. The young hydra develops a mouth and tentacles. Finally the tiny hydra detaches itself from the body of parent and lives as a separate organism. This method of asexual reproduction is called budding.

Question 35.
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Answer:
Multicellular organisms are not mass of random collection of similar cells. They consist of many different types of specialised cells, which are organized into tissues and tissues are organised into organs. These organs with different cell structures are located in specific positions of the body.

Regeneration happens through mitosis and a particular type of tissue can give rise to its own kind only. Hence, regenerating a different kind of tissue from another kind is not possible. Therefore, complex organisms cannot give rise to new individuals through regeneration.

Question 36.
What is the reproductive method in Leishmania, plasmodium and yeast?
Answer:
Leishmania, plasmodium and yeast reproduce by asexual methods. Leishmania reproduces by the method of binary fission. Plasmodium reproduces by multiple fission. Yeast reproduces by the method of budding.

Question 37.
What is vegetative propagation? Name some plants that are multiplied by this method.
Answer:
A form of asexual reproduction in plants, in which new plants grow from the vegetative parts, such as leaves, stem or roots, is called vegetative propagation. New plants of sugarcane, roses, grapes, banana, jasmine, rose etc., are grown by vegetative propagation.

Question 38.
Why is vegetative propagation considered as asexual reproduction?
Answer:
In vegetative propagation only one parent is involved and the offspring is genetically identical to the parent. This mode of reproduction does not involve the fusion of gametes. Therefore, vegetative propagation is considered as asexual reproduction.

Question 39.
Why is vegetative propagation practiced for growing some types of plants?
Answer:
Some plants do not produce seeds or they produce seeds from which a new plant cannot be grown. Vegetative propagation is practiced for growing such type of plants.

Question 40.
Give examples of three plants that have lost the ability to bear seeds.
Answer:
Examples of plants that have lost the ability to bear seeds include plantain, rose and jasmine.

Question 41.
List the advantages of vegetative propagation.
Answer:
The following are the advantages of vegetative propagation

1. The new plant is genetically a replica of the parent plant. Therefore, purity of the variety is maintained in vegetative propagation.
2. In this method, it is possible to propagate those plants that are not able to produce seeds.
3. New plants can be grown quickly by vegetative propagation. Plants raised by this method can bear flowers and fruits earlier than those produced by seeds.

Question 42.
How do you show vegetative propagation in potato?
Answer:
Potato is modified stem and therefore it is a vegetative part of the plant. Take a potato and cut it into small pieces such that some pieces contain a notch or bud and some do not. Spread some cotton on a tray and wet it. Place the potato pieces that contain notch and other pieces separately on the wet cotton.

Ensure that the cotton is kept moist all the time. Observe the changes taking place in the potato pieces over the next few days. It is observed that the potato pieces with notch will develop fresh green shoots and roots from the sites of notches.

Pieces of potato that have no notches do not develop shoots and roots. This shows that a new potato plant can be grown from a potato piece that has notches. This demonstrates vegetative propagation in potato.

Question 43.
How does a bryophyllum plant reproduce?
Answer:

Bryophyllum reproduces by vegetative propagation. There are notches along the leaf margin of bryophyllum. When a leaf of this plant falls into the soil, buds emerge from these notches and develop into new plants.

Question 44.
How does a money plant propagate itself?
Answer:
A money plant propagates vegetatively from its stem.

Question 45.
How does rhizopus reproduce? Explain.
Answer:
Rhizopus is a fungus. It reproduces asexually by spore formation. Rhizopus is a filamentous alga. The thread-like body structure of this organism is called hyphae. Each hyphae has a tiny blob called sporangia at its free end. These blobs contain ‘seeds’ of reproduction called spores.

Sporangia break and release spores to the surrounding medium. The spores are covered by thick walls that protect them until they get favourable conditions. When these spores come into contact with a moist surface, they begin to grow new filaments.

Question 46.
What are the reproductive structures in rhizopus called?
Answer:
The reproductive structures in rhizopus are called sporangia. These are blob-like structures that contain spores.

Question 47.
What is sexual reproduction?
Answer:
A type of reproduction, which involves the fusion of male and female gametes, is known as sexual reproduction.

Question 48.
What are the advantages of sexual reproduction?
Answer:
Sexual reproduction promotes genetic variability, favours the development of adaptive features, and speeds up evolution.

Question 49.
What is meiosis? What is its need?
Answer:
A type of cell division that results in daughter cells with half the number of chromosomes of the parent cell is called meiosis. Meiosis is required for producing reproductive cells such as gametes. Sexual reproduction allows for the production of unique offspring of the species with variable traits.

This becomes possible because the genetic material from two parents gets mixed and produces a unique combination. This requires that the daughter cells produced by cell division must contain only half the chromosomes present in the parent cell.

When this happens, the zygote can again become diploid and have the same number of chromosomes as the parent cell. Therefore, meiosis is necessary for sexual reproduction.

Question 50.
What are the advantaees of sexual reproduction over asexual reproduction?
Answer:
Sexual reproduction involves the fusion of male and female gametes and usually involves two parents. Since the characteristics are inherited from both the mother and the father, the offspring shows variation in characteristics. This is useful in adaptation and survival. The offspring in asexual reproduction are genetically identical to the parent and hence no variation is possible.

Question 51.
Distinguish between sexual reproduction and asexual reproduction.
Answer:
Sexual reproduction:

1. Involves the fusion of gametes.
2. Usually two parents are involved.
3. The offspring is unique.
4. The offspring is genetically different from the parents.
5. Produces genetic variations in characteristics.
6. One or more offspring are produced

Asexual reproduction:

1. Does not involve the fusion of gametes.
2. Only one parent is involved.
3. The offspring is a copy of the parent.
4. The offspring is genetically identical to the parent.
5. Does not produce any genetic variations in characteristics.
6. Two or more offspring are produced.

Question 52.
What are gametes? What are its types?
Answer:
Specialized cells, which are directly involved in the process of reproduction in higher order plants and animals, are called gametes. They are als called sex cells or germ cells. There are two types of gametes: Male gamete and female gamete. The male gamete is called sperm and the female gamete is called ovum (also called egg).

Question 53.
What is fertilization ?
Answer:
The fusion of a male sex cell and a female sex cell resulting in a single cell, which develops into a new organism, is called fertilization.

Question 54.
Give the meaning of the following terms: Gamete, gonads, sperm, ovum, fertilization, and zygote.
Answer:

• Gamete: The cells involved in sexual reproduction are called gametes.
• Gonads: The reproductive glands that produce sex cells are called gonads.
• Sperm: The male sex cell (male gamete) is called sperm.
• Ovum: The female sex cell (female gamete) is called ovum or egg.
• Fertilization: The fusion of sperm and ovum resulting in a single cell is called fertilization.
• Zygote: A fertilized ovum is called zygote.

Question 55.
Name the sex cell produced in female reproductive system and the sex cell produced in male reproductive system.
Answer:
The sex cell produced in female reproductive system is called egg or ovum. The sex cell produced in male reproductive system is called sperm.

Question 56.
Distinguish between male gamete and female gamete.
Answer:
Male gamete:

1. Male gamete is produced in the male reproductive system.
2. The male gamete in animals is called sperm.
3. Male gamete is usually motile and small in size.
4. Generally male gamete does not store food.

Female gamete:

1. Female gamete is produced in the female reproductive system.
2. Female gamete is called egg or ovum.
3. Female gamete is non-motile and usually bigger in size.
4. Female gamete generally stores food.

Question 57.
In which group of green plants do we find sexual mode of reproduction?
Answer:
We find sexual mode of reproduction in flowering plants, which are also known as angiosperms.

Question 58.
What are angiosperms? Name the organ of reproduction in angiosperms.
Answer:
Plants that bear seeds that are enclosed in fruit are called angiosperms. These are also known as flowering plants. The organ of reproduction in angiosperms is flower.

Question 59.
Draw a labelled diagram of the loneitudinal section of a flower.
Answer:

• Pistil – Female reproductive part
• Stigma – Terminal part of pistil; the part that receives pollen
• Style – Middle elongated part of pistil; the connective tissue between stigma and ovary
• Ovary – Bottom part of pistil; the part that contains ovules
• Stamen – Male reproductive part; the part that produces pollen grains
• Anther – Pollen-producing organs
• Filament – Stalk supporting anthers .
• Petals – Collectively called corolla
• Sepals – Collectively called calyx; protective leaf-like enclosures for the flower buds
• Stamen (Male) – Anther, Filament
• Pistil or carpel (Female) – Stigma, Style, Ovary

Question 60.
Which are the four prominent parts (whorls) present in a typical flower?
Answer:
The four prominent parts in a typical flower are sepals, petals, stamens and carpels.

Question 61.
What is a sepal? What is its function?
Answer:
The outermost whorl of a flower consisting of green coloured units is called sepal. The sepals protect the flower, especially in the bud condition.

Question 62.
What are petals? What is its function?
Answer:
As we move from outside towards inside of a flower, the second whorl consists of bright coloured segments called petals. Petals are modified leaves that surround the reproductive parts of flowers. Together, all of the petals of a flower are called a corolla. Petals protect the reproductive parts that lie inside the flower. Their function is to attract insects for pollination.

Question 63.
What are stamens ? What is their function?
Answer:
TheThe male reproductive structures in a flower are called stamens. The chief function of stamens is to produce pollen grains, which produce male sex cells.

Question 64.
What are carpels? What is each carpel made of? What is their function?
Answer:
The female reproductive structures in a flower are called carpels. Each carpel consists of an ovary, which contains one or more ovules, a style and the stigma. A carpel in a flower consists of ovary, style and stigma.

The ovary of a carpel produces ovules. The ovule produces female sex cells. The ovary protects the ovule. After fertilisation, the ovule will become the fruit. The style of a carpel is a tubular structure between the stigma and the ovary.

The style helps the movement of pollens from the stigma to the ovary. Stigma is the receptacle for pollen. It has a sticky surface so that pollens stick. The stigma also transports the pollen to the ovum for fertilization.

Question 65.
Describe briefly the structure of a carpel.
Answer:
Each carpel consists of an ovary, which contains one or more ovules, a style and the stigma. The ovary is at the base of the flower. A tubular structure that extends from the ovary is called the style. The top of the style is a surface called stigma, which receives pollens.

Question 66.
Name the structure that gives rise to and contains the female reproductive cells in a flower. Where is it located?
Answer:
The structure that gives rise to and contains the female reproductive cells in a flower is called ovule. It is located inside the ovary.

Question 67.
Which are the male and female reproductive parts in a flower?
Answer:
Stamens and carpels are the reproductive parts in a flower. Stamen is the male reproductive part and carpel is the female reproductive part in a flower.

Question 68.
What are unisexual flowers? Give two examples.
Answer:
Flowers, which contain either stamen or carpel, are called unisexual flowers. Such flowers will have to undergo only cross-pollination. For example, flowers of papaya and watermelon are unisexual.

Question 69.
What are bisexual flowers? Give two examples.
Answer:
Flowers that contain both stamen and carpel are called bisexual flowers. Such flowers can undergo both self-pollination and cross-pollination. Example: Mustard, hibiscus, etc.

Question 70.
Which are the two major steps involved in reproduction in angiosperms?
Answer:
Angiosperms reproduce by sexual method. Reproduction in angiosperms involves two steps namely pollination and fertilization.

Question 71.
What are pollen grains? What do pollen grains contain?
Answer:
A fine powdery substance, typically consisting of microscopic yellow grains discharged from the stamen of a flower is called pollen grain. Each grain of pollen contains a male gamete that can fertilize the egg.

Question 72.
What is pollination ? Mention its importance in reproduction.
Answer:
The transfer of pollen from the anther of a flower to the stigma of the same flower or of another flower is called pollination. Pollination is a prerequisite for fertilization. Seeds cannot form without pollination.

Question 73.
Name the two types of pollination found in plants.
Answer:
The two types of pollination in plants are

• self-pollination
• cross-pollination.

Question 74.
Distinguish between self-pollination and cross-pollination.
Answer:
The transfer of pollen from the anther of a flower to the stigma of the same flower is called self-pollination. The transfer of pollen from the anther of a flower to the stigma of another flower of the same plant or a different plant of the same species is called cross-pollination.

Question 75.
What is fertilization in plants? When and where does it occur?
Answer:
The fusion of male and female gametes resulting in the formation of a zygote in a flowering plant is known as fertilization. Fertilization occurs after pollination. Fertilization occurs in the ovaries.

Question 76.
How do pollens reach the ovaries of a flower? Explain.
Answer:
Pollen somehow gets deposited on the stigma of the carpel. For fertilization to occur, these pollens must reach the ovule through the style. The pollen grains on the stigma of a flower will develop a pollen tube that extends up to the ovule through the style. Pollens, which carry the male sex cells, will now move through the pollen tube.

Once the pollen tube reaches an ovule, it delivers sperm cells with a burst, which goes to the embryo sac. The sperm cell fertilizes the egg cell to form an embryo, which will develop into a seed. The seed is a potential future plant.

Question 77.
Draw a neat, labelled diagram showing the germination of pollen on stigma.
Answer:

Question 78.
After fertilization in a flower, which part develops into fruit, seed coat and seed?
Answer:
After fertilization in a flower, the ovary grows rapidly and ripens to form a fruit. The ovule becomes a seed. The covering of the ovule develops into seed coat.

Question 79.
What changes occur in the flower after pollination and fertilization?
Answer:
After pollination and fertilization get over, the following changes occur in the flower

1. The embryo develops into a seed, which later can grow into a new plant.
2. A nutritive tissue develops around the embryo, which stores nutrients.
3. The covering of the ovule forms the seed coat.
4. Ovary part of the carpel gets transformed into a fruit.
5. Sepals, petals and other parts of the flower will fall off.

Question 80.
What are the advantages of seed formation for a plant?
Answer:
Seed formation provides the following advantages to a plant

1. Seeds have reserve food sources which provide nourishment to the developing embryo.
2. They protect the embryo from harsh environmental conditions and enable the embryo to survive for long periods.
3. The seeds are easily dispersed by natural agents. The dispersal of seeds to far-off places prevents competition among the members of the same species, thus preventing their extinction.
4. Seeds can survive without water. If there is a drought, the plants can survive.
5. Seeds are produced in large numbers, which facilitates plants to multiply.

Question 81.
How is the process of pollination different from fertilisation?
Answer:
Transfer of pollen grains from anther to stigma is called pollination. On the other hand, fusion of male and female gametes is called fertilization. Pollination is a physical process in which movement of pollen grains is achieved by certain physical factors. Fertilization is a biological process.

Ovary is the site of fertilization and embryo is the product of fertilization. Pollination involves only the male gamete (pollen grain). Fertilisation involves both male and female gametes.

Question 82.
What is germination of a seed? Explain.
Answer:
The development of a plant from a seed is called seed germination. The development of a seed into a plantlet after it has been planted in soil and remained dormant for a certain period of time is called germination. When seeds get into the soil, they remain inactive until conditions are suitable for germination. When they get favourable conditions, they germinate and a new young plant emerges.

Question 83.
Describe a simple activity to show the different parts of a seed.
Answer:

Soak a.few seeds of Bengal gram and keep them overnight. Drain the excess water. Cover the soaked seeds with a wet cloth and leave them for a day. Make sure that the seeds do not become dry. Cut open the seeds carefully and observe the different parts.

We observe the brownish seed coat that encloses the two cotyledons. The cotyledons are laden with stored food material which help the seedling in the early stage of its development. We can also see a small embryo in between the two cotyledons.

Question 84.
What type of reproduction and development happens in humans?
Answer:
Fluman beings reproduce by sexual method. The development is direct. This means a newly born baby resembles the adult in appearance, body parts and their functioning.

Question 85.
What is fertilization? Where does it occur in humans?
Answer:
The process of formation of a single cell by the union of male sex cell (sperm) and female sex cell (ovum) is called fertilization. In humans, fertilization is internal. It occurs inside the female body.

Question 86.
What is a zygote? Compare the number of chromosomes present in a sex cell with those present in the zygote.
Answer:
A single cell formed by the union of male gamete and female gamete is called zygote. Zygote contains twice the number of chromosomes present in a sex cell that caused its formation.

Question 87.
Why are sex cells said to be haploid?
Answer:
Both the male sex cell (sperm) and the female sex cell (ovum) contain half the number of chromosomes present in other cells of the organism. For example, the cells in our body contain 46 chromosomes. However, the male and female sex cells of a human being will have only 23 chromosomes each. This is why sex cells are said to be haploid.

Question 88.
A flowering plant has 24 chromosomes in its male gamete,

1. How many chromosomes are present in its female gamete?
2. What is the number of chromosomes in its zygote?

Answer:

1. 24 chromosomes (both gametes should contain same number of chromosomes).
2. 48 chromosomes are present in its zygote. The union of male and female gametes forms zygote and hence the chromosomes add up.

Question 89.
What is puberty?
Answer:
The period in life when a boy or girl becomes sexually mature and capable of sexual reproduction is called puberty. It is marked by several marked changes in the body. It is associated with the development of secondary sex characteristics and rapid growth. It is a process that usually happens between ages 10 and 14 in girls and ages 12 and 16 in boys.

Question 90.
What are the changes seen in eirls at the time of puberty?
Answer:
The following changes are seen in girls at the time of puberty

1. The size of the breasts begins to increase.
2. Hairs grow in the arm pits and around the genitals.
3. The nipples at the tip of the breasts become relatively dark.
4. Menstruation cycle begins at around this time and continues periodically.
5. The voice becomes shriller and more feminine.
6. The pelvic region becomes broader.
7. The reproductive organs mature and become functional.

Question 91.
What are the changes seen in boys at the time of puberty?
Answer:
The following changes are seen in boys at the time of puberty

1. Hairs appear in armpits, around the genitals, face (beard and moustach) and all over the body.
2. The voice breaks and becomes hoarse.
3. Gain height and weight. Hairs may appear on the chest.
4. The body becomes muscular and shoulders broaden.
5. Reproductive organs develop and become functional.

Question 92.
What are some of the common changes observed in boys and girls at puberty?
Answer:
The following are some of the common changes in boys and girls during puberty:

1. Hairs appear in both boys and girls in armpits and genital area between the thighs.
2. The genital area becomes darker in both boys and girls.
3. Hairs on arms and legs appear and become darker.
4. The skin becomes oily and pimples may appear on the face in both boys and girls.
5. Both boys and girls become conscious of their own body as well as those of others.

Question 93.
Name the parts of the male reproductive system in humans.
Answer:
The male reproductive system in humans consists of

• two testicles (testes)
• the duct system that includes epididymis and vas deferens
• the accessory glands which include seminal vesicles and prostate gland, and
• penis.

Question 94.
Draw a diagram of the male reproductive system in humans and label the parts.
Answer:

Question 95.
What are testes? Where are they located in the human body?
Answer:
Oval shaped reproductive gland in the body of a human male is called testis. There are two testes in the human body. Testes are located within the loose pouch of skin called scrotum that hangs outside the body behind the penis.

Question 96.
What is scrotum? What is their function?
Answer:
A small muscular sac, which forms a part of the external male genitalia located behind and underneath the penis and houses the testicles is called scrotum. The scrotum holds and protects the testicles and keeps them at the right temperature.

The production of sperms requires relatively lower temperature and therefore the temperature in the scrotum is lesser than the temperature of the rest of the body. Under cold conditions, scrotum pulls the testicles closer to the body and when the conditions are warmer, testicles hang away from the body.

Question 97.
What are the functions performed by the testis in human beings?
Answer:
Testis in human beings has twin functions. It produces male gametes namely the sperms. It also produces male sex hormone called testosterone, which is responsible for the development of secondary sexual characteristics in males.

Question 98.
What is a sperm? Describe the structure of a sperm cell.
Answer:
The male reproductive cell is called sperm. A human sperm cell consists of an oval shaped head, a mid-piece and a long tail. The tail helps to make the sperm move easily in a fluid medium.

Question 99.
What is the function of the tail in a sperm?
Answer:
The long tail of a sperm has a wavy motion with the help of which the sperm cell moves easily to the site of fertilization in the body of a female.

Question 100.
What is sperm duct? What is its other name? What is its function?
Answer:
The duct that conveys sperms in a male from the testicle to the urethra is called sperm duct. It is also called vas deferens. It is a coiled duct that provides a pathway for the transport of sperms to the penis.

Question 101.
What is penis? What is its function?
Answer:
The external muscular genital structure in males that carries the duct for the transfer of sperms to the female body is called penis. Biologically, penis has two main functions. It is an organ for urination, and passing on the sperms to the reproductive system of the female body for procreation.

Question 102.
Name any two reproductive accessory glands in the body of humans.
Answer:
The accessory glands associated with the reproductive system in humans include seminal vesicles and prostate gland.

Question 103.
What is the role of the seminal vesicles and the prostate eland?
Answer:
Seminal vesicles and prostate gland form an important part of the male reproductive system. The seminal vesicles and prostate gland add their secretions to sperms to make up the semen. The secretions of seminal vesicles and prostate gland provide nutrition to the sperms and also provide a suitable medium for their easy transport.

Question 104.
How are the sperms produced in testes delivered to the female body for fertilization?
Answer:
Sperms are produced in the testes and are stored there temporarily. They are delivered through the vas deferens, which unites with a tube coming from the urinary bladder. The urethra thus forms a common passage for both the sperms and urine. Along the path of the vas deferens, glands like the prostate and the seminal vesicles add their secretions to the sperms to form semen.

The sperms are now in a fluid medium, which makes their transport easier. The substances in the fluid will also provide nutrition to the sperms. The semen containing sperms is delivered by the penis into the vaginal passage of the female during intercourse. The sperms further travel upwards and reach the oviduct where one of the sperms may fertilize the egg.

Question 105.
Mention the three major functions of the female reproductive system.
Answer:
The three major functions of the female reproductive system are

• production of eggs (ovum),
• protection and nourishment of the fertilized egg until it fully develops into a baby, and
• giving birth to the baby.

Question 106.
Mention the parts of the female reproductive system in humans.
Answer:
The female reproductive system in humans consists of

• A pair of ovaries
• A pair of fallopian tubes
• Womb, and
• Vagina.

Question 107.
Dr aw a neat diagram of the female reproductive system in humans and label the parts.
Answer:

Question 108.
What are ovaries? What is their main function?
Answer:
A pair of oval-shaped glands of the female reproductive system that are located slightly above the uterus on its either side and involved in the production of female sex cells is called ovaries. The main function of the ovaries is to produce ova or eggs. They also produce female hormones.

Question 109.
What are fallopian tubes? What is their function?
Answer:
Either of the two tubes that connects ovary to the uterus is called fallopian tube. They are also called oviducts. Oviducts help the eggs produced in ovaries to move towards or into the uterus.

Question 110.
What is uterus? Where is it located?
Answer:
A sac-like elastic organ in the female reproductive system, shaped in the form of an inverted triangle, into which the oviducts open is called uterus. It is also called womb. Uterus is located in the lower abdomen of a woman, between rectum and urinary bladder.

Question 111.
What are the functions of uterus ?
Answer:
The uterus has several important functions. It includes receiving the developing zygote, implantation, gestation, labour, delivery and menstruation. Most importantly, the fertilized egg develops into a human baby inside the uterus.

Question 112.
What is vagina? What are its functions?
Answer:
An elastic, muscular canal with a soft, flexible lining that is connected to the uterus is called vagina. The vagina receives the semen and helps to pass the sperms to the fallopian tube through the uterus. It also serves as an outlet for menstrual flow from the uterus. During childbirth, the vagina expands to facilitate the passage of the baby during childbirth.

Question 113.
In which part of the female reproductive system does fertilization occur?
Answer:
Fertilization occurs in the fallopian tube (oviduct).

Question 114.
What is zygote? Where does it get formed? What happens to it after its formation?
Answer:
The single cell formed by the union of a sperm and ovum is called zygote. It is nothing but a fertilized ovum. Zygote is formed in the fallopian tube when a sperm succeeds in entering into the ovum. Fertilization results in the formation of the zygote.

The zygote undergoes cell division for about 5-6 days in the fallopian tube itself to form a small spherical mass. This mass enters the uterus and gets implanted on its wall. The embryo develops there until the baby is born.

Question 115.
Distinguish between a gamete and zygote. Explain their roles in sexual reproduction.
Answer:

Gamete	Zygote
1. The cells involved in sexual reproduction are called gametes. E.g.: sperm (male) and ova (female)	The fusion of male gamete and female gamete forms zygote during sexual reproduction.
2. Gametes are unfertilised reproductive cells.	Zygote is fertilised egg or fertilised ovum.
3. The fusion of sperm and egg forms a fertilised ovum or zygote.	Zygote undergoes development and forms a new organism.

Question 116.
What is implantation? What is its significance to a woman?
Answer:
The attachment of the fertilized egg or a ball of mass formed from it, to the wall of the uterus is called implantation. Implantation signifies that the woman has become pregnant. It marks the beginning of pregnancy.

Question 117.
What is a human embryo?
Answer:
The collection of human cells developed from the fertilized egg, especially from implantation on the uterine wall and the eighth week, is called embryo. This is the early stage of development before differentiation of the body parts occurs.

Question 118.
What is placenta? What are its functions?
Answer:
A disc-shaped special tissue embedded in the uterus wall with the help of which human embryo gets nutrition from mother’s blood is called placenta. Placenta provides large surface area for the passage of nutrients and oxygen from the mother’s blood to the embryo. The metabolic waste generated by the embryo is removed through the placenta into mother’s blood.

Question 119.
What is the role of placenta during pregnancy?

OR

Placenta is extremely essential for foetal development. Give reason.
Answer:
Placenta in the womb serves as the connecting link between mother’s blood and the growing embryo during pregnancy. It has ftnger-like projections called villi. The villi increase the surface area for fixation and absorption.

They serve as the passage for nutrients and oxygen from the blood of the mother to the embryo. They also serve as the passage for waste materials to move out of the embryo into the mother’s blood.

Question 120.
‘The structure and function of placenta plays an important role at the time of gestation period’. Explain.
Answer:
Placenta has a disc shaped structure that is embedded in the wall of the uterus. It has finger-like projections called villi. This provides the placenta a large surface area for the passage of nutrients and oxygen from the blood of the mother to the embryo. It also serves as the passage for waste materials to move out of the embryo into the mother’s blood.

Question 121.
What is menstruation? Explain.
Answer:
The discharging of blood and other materials from the lining of the uterus at intervals of about one month from puberty until menopause is called menstruation. Before ovulation, the uterus prepares itself to receive the developing zygote. The walls of the uterus become thick and spongy with plenty of blood supply.

If the egg is not fertilized, the soft tissues of the lining of the uterus break down. The broken tissues along with blood and the unfertilized egg are discharged from the uterus through the vagina. This flow of materials through the vagina is known as menstruation. A woman will generally experience menstrual flow from 2 to 8 days.

Question 122.
What is menstrual cycle? What is its period? How long does a woman discharge blood and other materials through the vagina during menstruation?
Answer:
The monthly cycle of changes in the ovaries and the lining of the uterus starting with the preparation for ovulation is called menstrual cycle. The period of the menstrual cycle is about 28 days.

Question 123.
What happens when fertilization fails to occur in a woman?

OR

Why does menstruation occur?
Answer:
The menstrual cycle begins when a girl reaches the age of puberty. It is the reproductive cycle that produces egg for fertilisation. During the menstrual cycle the uterus prepares itself every month for implantation and nurturing of the embryo. The lining thickens and is richly supplied with blood to nourish the growing embryo.

If fertilization and implantation do not occur, the uterus lining is shed from the body and moves out through the vaginal opening. This is how menstruation occurs when fertilization and implantation do not take place.

Question 124.
How does the embryo in the mother’s womb develop into a baby?

OR

How does the embryo get nourishment inside the mother’s body?
Answer:
The fertilized egg (zygote) turns into a mass of cells in the fallopian tube and gets implanted in the uterus. The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. This is a disc that is embedded in the uterine wall. It contains villi on the embryo’s side of the tissue.

On the mother’s side are blood spaces, which surround the villi. This provides a large surface area for glucose and oxygen to pass from the mother to the embryo. The developing embryo will also generate waste substances. These are transferred to the mother’s blood through the placenta.

The development of the child inside the mother’s body takes approximately nine months. The child is born as a result of rhythmic contractions of the muscles in the uterus.

Question 125.
What are sexually transmitted diseases? Give examples.
Answer:
Those infections that can be transmitted through sexual contact with an infected individual are called sexually transmitted diseases. They are also called sexually transmitted infections. Sometimes, they are also called venereal diseases. eg: Syphilis, Gonorrhoea, Genital herpes, AIDS etc.

Question 126.
How are sexually transmitted infections passed from one person to another?
Answer:
Sexually transmitted infections are usually transmitted from one person to another when individuals engage in intimate sexual activity with someone who is infected.

Question 127.
Define pregnancy.
Answer:
The period between conception and birth during which a foetus develops into an infant baby inside a woman’s womb or uterus is called pregnancy.

Question 128.
What is contraception? What are the various types of contraception available to people?
Answer:
Any technique, procedure or device used to prevent pregnancy as a consequence of sexual intercourse is called contraception.
The following are some of the types of contraception employed by people to prevent possible pregnancy
1. Mechanical barrier method:
This technique employs a barrier that prevents the sperm from meeting the egg. eg: Use of condoms (males), cervical caps (females), and diaphragms.

2. Hormonal method:
This technique causes changes in hormonal balance, which prevents the release of egg. eg: Use of oral pills.

3. Use of IUD:
This technique employs placement of a device that either releases copper or hormones, which prevents pregnancy. eg: Copper-T, loop etc.

4. Surgical method:
This technique aims at preventing the passage of sperms in males and ova in females. eg: Tubectomy for females and vasectomy for males.

Question 129.
Write the expandedforms of the following: HIV, AIDS, IUD, and DNA.
Answer:

• HIV: Human Immunodeficiency Virus.
• AIDS: Acquired Immunodeficiency Syndrome.
• IUD: Intra-Uterine Device.
• DNA: Deoxyribonucleic Acid.

Question 130.
What are the different methods of contraception?
Answer:
The various methods of contraception include the use of condoms (both men and women), copper-T, oral pills, spermicidal pills, tubectomy and vasectomy.

Question 131.
What could be the reasons for adoptins contraceptive methods?
Answer:
The main reason for adopting contraceptive methods is to prevent unwanted pregnancy. Some contraceptive methods will also give protection against sexually transmitted diseases.

Question 132.
A woman is using copper-T to prevent pregnancy. Will this device give protection against sexually transmitted diseases?
Answer:
No. The use of copper-T will not give protection from sexually transmitted diseases.

Question 133.
What could be the reasons for adopting condom as a contraceptive method?
Answer:
Use of condoms helps to prevent unwanted pregnancy and childbirth as a consequence of sexual intercourse. The use of condoms will give protection against sexually transmitted diseases.

Question 134.
How will vasectomy and tubectomy prevent pregnancy? Explain.

OR

How can pregnancy be prevented surgically?
Answer:
Tubectomy and vasectomy are surgical techniques of contraception. Tubectomy is performed on women while vasectomy is performed on men. In women, the fallopian tubes are cut and then the cut ends are tied, burned, or clipped.

Any of these methods prevents the eggs from travelling from the ovaries to the uterus. In men, the vas deferens is cut and then the cut ends are tied so that sperms eannot mix with semen.

Question 135.
What is sex ratio? Why is it falling in our country?
Answer:
The number of females for every 1000 males in a population is called sex ratio. The sex ratio in our country is falling due to the preference of parents for male children. This bias is reflected in reckless female foeticides, killing of female babies, neglect of girl children and discrimination against women. As a result of all these, the sex ratio in our country is falling.

Fill In The Blanks:

1. Amoeba usually reproduces asexually by binary fission
2. The male reproductive cell is called sperm
3. A single cell, which emerges as the product of fertilization, is called zygote
4. The part of the flower that develops into a fruit is ovary
5. Pollen grain in a flower contains a male gamete
6. Surgical method used on females to prevent pregnancy is tubectomy
7. The mode of reproduction that does not involve the fusion of gametes is called asexual reproduction
8. The primary genital organ in human males is called testis
9. The primary genital organ in human females is called ovary
10. The process by which the embryo in a seed develops into a seedling is called germination
11. A single cell formed by the fusion of an egg and a sperm is called zygote
12. Somatic cells : Diploid :: Germ cells : Haploid

Multiple Choice Questions:

Question 1.
sexual reproduction takes place through budding in
(A) amoeba.
(B) yeast.
(C) plasmodium.
(D) leishmania.
Answer:
(B) yeast.

Question 2.
Which of the following is not a part of the female reproductive system in human beings?
(A) Ovary
(B) Uterus
(C) Vas deferens
(D) Fallopian tube
Answer:
(C) Vas deferens

Question 3.
The anther contains
(A) sepals.
(B) ovules.
(C) carpel.
(D) pollen grains.
Answer:
(D) pollen grains.

Question 4.
Vegetative propagation refers to the formation of new plants from
(A) stem, roots, and flowers.
(B) stem, roots, and leaves
(C) stem, flowers, and fruits
(D) stem, leaves, and flowers.
Answer:
(B) stem, roots, and leaves

Question 5.
A feature of reproduction that is common to amoeba, spirogyra and yeast is that
(A) they reproduce asexually
(B) they are all unicellular
(C) they reproduce only sexually
(D) they are all multicellular.
Answer:
(A) they reproduce asexually

Question 6.
The correct sequence of reproductive stages seen in flowering plants is
(A) gametes → zygote → embryo → seedling
(B) zygote → gametes → embryo → seedling
(C) seedling → embryo → zygote → gametes
(D) gametes → embryo → zygote → seedling
Answer:
(A) gametes → zygote → embryo → seedling

Question 7.
Characteristics that are transmitted from the parents to their offspring are present in
(A) cytoplasm
(B) golgi bodies
(C) ribosomes
(D) genes
Answer:
(D) genes

Question 8.
The number of chromosomes in parents and offspring of a particular species remains constant due to
(A) doubling of chromosomes after gamete formation
(B) doubling of chromosomes after zygote formation
(C) halving of chromosomes after gamete formation
(D) halving of chromosomes during gamete formation
Answer:
(D) halving of chromosomes during gamete formation

Question 9.
Offspring formed as a result of sexual reproduction exhibit more variations because
(A) sexual reproduction is a lengthy process
(B) genetic material comes from two parents of the same species
(C) genetic material comes from two parents of different species
(D) genetic material comes from many parents
Answer:
(B) genetic material comes from two parents of the same species

Question 10.
The sequential route followed by sperms in the female reproductive system is
(A) vagina, fallopian tube, uterus
(B) uterus, vagina, fallopian tube
(C) vagina, uterus, fallopian tube
(D) fallopian tube, uterus, vagina
Answer:
(C) vagina, uterus, fallopian tube

Question 11.
The process of the union of an egg and a sperm is known as
(A) Asexual reproduction
(B) Multiple fission
(C) Zygote
(D) Fertilization
Answer:
(D) Fertilization

Question 12.
The event that marks the beginning of the reproductive phase in human females is
(A) changes in voice pattern
(B) menstruation (menarche)
(C) changes in hair pattern
(D) increase in height and weight
Answer:
(B) menstruation (menarche)

Question 13.
Hydra reproduces asexualiy by
(A) budding
(B) binary fission
(C) multiple fission
(D) vegetative propagation
Answer:
(A) budding

Question 14.
In a flower, the parts that produce male and female gametes (germ cells) are respectively
(A) stamen and anther
(B) filament and stigma
(C) anther and ovary
(D) stamen and style
Answer:
(C) anther and ovary

Question 15.
The mode of asexual reproduction in which the parent cell divides into many daughter cells is
(A) Binary fission
(B) Budding
(C) Fission
(D) Multiple fission
Answer:
(D) Multiple fission

Question 16.
During adolescence, several changes occur in the human body. A change that represents the development of secondary sexual characteristic in boys is
(A) loss of milk teeth
(B) increase in height
(C) cracking of voice
(D) weight gain
Answer:
(C) cracking of voice

Question 17.
Characteristics that are transmitted from parents to offspring during reproduction show
(A) only similarities with parents
(B) only variations with parents
(C) both similarities and variations with parents
(D) neither similarities nor variations with parents
Answer:
(C) both similarities and variations with parents

Question 18.
The part of a potato plant that can be propagated vegetatively is
(A) stem
(B) root
(C) leaves
(D) flowers
Answer:
(A) stem

Question 19.
Reproduction is essential for living organisms in order to
(A) keep the individual organism alive
(B) meet the energy requirement of the organism
(C) maintain growth
(D) ensure the continuation of species generation after generation
Answer:
(D) ensure the continuation of species generation after generation

Question 20.
Advantages of artificial methods of vegetative propagation include
(A) crops with better quality
(B) crops with more yield
(C) ability to produce plants with desirable qualities
(D) all of the above
Answer:
(D) all of the above

Question 21.
Which of the following reproduces by spore formation?
(A) Planaria
(B) Rhizopus
(C) Spirogyra
(D) Yeast
Answer:
(B) Rhizopus

Question 22.
Which one of the following is not a part of the male reproductive system in human beings?
(A) Fallopian tube
(B) Penis
(C) Testis
(D) Vas deferens
Answer:
(A) Fallopian tube

Question 23.
The correct sequence of organs in the male reproductive system for the transport of sperms is
(A) testis → vas deferens → urethra
(B) testis → ureter → urethra
(C) testis → urethra → ureter
(D) testis → vas deferens → ureter
Answer:
(A) testis → vas deferens → urethra

Question 24.
A disadvantage of natural vegetative propagation is that it
(A) lacks dispersal mechanisms for propagation
(B) does not involve production of gametes and fertilization
(C) quickly spreads and colonizes the entire area with similar plants
(D) produces daughter plants quickly which start yielding products
Answer:
(A) lacks dispersal mechanisms for propagation

Question 25.
The reason for increase in human population is
(A) improvement in health care services.
(B) the increase in birth rate and decrease in death rate.
(C) the increase in agricultural production.
(D) All of the above
Answer:
(D) All of the above

Question 26.
Offsprings of plants receive/possess varied characteristics in
(A) cross-pollination
(B) self-pollination
(C) wind pollination
(D) insect pollination
Answer:
(A) cross-pollination

Question 27.
The correct order of binary fission in Leishmania is

(A) II, III, IV, I
(B) I, III, IV, II
(C) IV, I, III, II
(D) III, I, II, IV
Answer:
(B) I, III, IV, II

Match The Following:

Column A	Column B
1. Ovulation	(a) Termination of human pregnancy
3.  Fertilization	(b) Attained during puberty
5.  Implantation	(c) Production of sperms in testis
7.  Sexual maturation	(d) Release of egg from the ovary
8.  Menstruation	(e) Attachment of zygote to uterine wall
10. Abortion	(f) Union-of sperm and egg
	(g) Monthly discharge from the vagina

Answer:
1 – d, 2 – f, 3 – e, 4 – b, 5 – g, 6 – a.

Column A	Column B
1. Testis	(a) Male sex cell
2. Scrotum	(b) Produces male germ cells
3. Ovary	(c) Female gamete
4. Sperm	(d) Product of fertilization
5. Ovum	(e) Houses testicle
	(f) Releases egg

Answer:
1 – b, 2 – e, 3- f, 4 – a, 5 – c.