NCERT Solutions for Class 9 Science Exploration Chapter 11 Reproduction: How Life Continues 2026-27

Revise, Reflect, Refine (NCERT Textbook Page No. 225)

Question 1. A flower’s anthers are removed before it matures. Later, pollen from another plant of the same species is dusted onto its stigma and seeds are produced. Which process has been ensured here?
(i) Self- pollination
(ii) Cross-pollination
(iii) Fertilisation
(iv) Tissue culture

Answer: (ii) Cross-pollination

Here, the anthers are removed so that the flower cannot use its own pollen. When pollen from another plant of the same species is placed on its stigma, the process becomes cross-pollination.

Question 2. Arrange the following stages of sexual reproduction in plants in the correct order:
(i) Pollen germination on stigma
(ii) Fertilisation
(iii) Pollination
(iv) Formation of zygote

Answer:
The correct order is:

(iii) Pollination → (i) Pollen germination on stigma → (ii) Fertilisation → (iv) Formation of zygote

First, pollen reaches the stigma. Then it germinates and forms a pollen tube. After that, fertilisation occurs, leading to the formation of a zygote.

Question 3. Assertion (A): The zygote formed after fertilisation immediately attaches to the uterus wall.
Reason (R): The uterus wall is always prepared to receive the zygote.
(i) Both A and R are true, and R is the correct explanation of A.
(ii) Both A and R are true, but R is not the correct explanation of A.
(iii) A is true, but R is false.
(iv) A is false, but R is true.

Answer: (iv) A is false, but R is true.

The zygote does not attach to the uterus wall immediately after fertilisation. It first undergoes several cell divisions and then implants in the uterus. The uterus lining is prepared to support the embryo during the reproductive cycle.

Question 4. Why does asexual reproduction produce offsprings that are genetically identical to the parent?

Answer: Asexual reproduction produces genetically identical offspring because only one parent is involved and there is no fusion of gametes. The new individual is formed by mitotic division, in which the parent’s DNA is copied and passed on. So, the offspring have the same genetic material as the parent and are called clones.

Reproduction How Life Continues Class 9 Question Answer Science Exploration Chapter 11

Question 5. Explain why the menstrual cycle stops during pregnancy.

Answer: During pregnancy, the uterine lining is maintained to nourish and support the developing embryo. Since this lining is not shed, menstruation does not occur. Hormones released during pregnancy help maintain the uterus and stop the menstrual cycle.

Question 6. Why are flowers that bloom at night white or light in colour as compared to flowers that bloom during the day?

Answer: Night-blooming flowers are usually white or light-coloured because such colours are easier to see in dim light. This helps attract night-time pollinators such as moths and bats. Many of these flowers may also have a strong fragrance to attract pollinators.

Question 7. Why do vegetatively propagated plants tend to be more vulnerable to diseases than sexually reproduced plants?

Answer: Vegetatively propagated plants are genetically identical to the parent plant. Since there is very little variation, all plants may have the same weakness against a disease. If one plant is affected, many others can also get infected easily.

Question 8. If all flowers in a type of plant were only capable of self-pollination, how would it affect the genetic diversity over several generations? Explain.

Answer: If a plant reproduces only by self-pollination for many generations, genetic diversity will gradually decrease. The offspring will be very similar to the parent plant.

This can make the plant population less adaptable to changes in the environment. It may also increase the risk of diseases affecting many plants at the same time.

Question 9. A farmer wants to produce a large number of genetically identical plants quickly. Suggest suitable reproduction methods and explain why they are effective.

Answer: The farmer can use asexual methods such as cutting, layering, grafting, vegetative propagation, or tissue culture.

These methods are useful because they produce plants that are genetically identical to the parent. They are also faster than growing plants from seeds. Tissue culture is especially helpful when a large number of identical plants need to be produced in a short time.

Question 10. Suresh prepares slides with pollen grains in thiferent sugar concentrations (0%, 2.5%, 5%, 7.5%, 10%) to study the germination of pollen.
(i) What are the different hypotheses which can be tested using this setup?
(ii) What parameters should be kept the same in this setup?

Answer:
(i) The following hypotheses can be tested:

• Pollen germination depends on the concentration of sugar solution.

• There is a particular sugar concentration at which pollen germination is maximum.

• Very low or very high sugar concentration may reduce or stop pollen germination.

(ii) The following parameters should be kept the same:

• Type and source of pollen grains

• Amount of sugar solution used on each slide

• Temperature and light conditions

• Time allowed for germination

• Method of slide preparation

• Number of pollen grains observed

Keeping these factors constant ensures that only sugar concentration affects the result.

Question 11. Look at the picture given below and think in line with the given prompts and find out which type(s) of pollination might have been followed in these flowers –

Answer:
Based on the features shown:

Tomato: Self-pollination is likely because the stamens are close to the stigma, allowing pollen to reach the stigma of the same flower.

Wheat: Self-pollination may occur before the flower opens. This type of pollination helps ensure seed formation.

Papaya: Cross-pollination is necessary because male and female flowers are present on different plants. Pollen must be transferred from the male plant to the female plant.

Question 12. In the lower Himalayan region of northern India, apples are an important cash crop that contribute significantly to farmer’s livelihoods. The fruit yield in apple cultivation is declining continuously, associated with climate change and a significant decline in the population of natural pollinators. A researcher-farmer group set up two experimental apple orchards at two distinct locations: Places A and B. In apple orchards at Place A, they allowed natural pollinators to pollinate the flowers of the apple.

In apple orchards at Place B, they applied mixed farming techniques of beekeeping. Along with honey, the farmer yielded apples. The yield of apples is depicted in Fig. 11.24, in terms of fruit setting (number of fruits/the total number of corresponding fruit-bearing branches) and fruit drop (premature faffing of developing fruits) in the two types of experimental places of apple orchards.

(i) What are the hypotheses the researcher-farmer group has thought of for this investigation?
(ii) What are the different parameters in the experiment?
(iii) Compare and analyse the data of two experimental orchards, Places A and B, in terms of high yields of apple fruits.
(iv) Based on your analysis, what do you infer from the data?

Answer:
(i) The possible hypotheses are:

• Beekeeping improves pollination in apple orchards.

• Better pollination increases fruit setting.

• The presence of bees reduces fruit drop and improves apple yield.

• A decline in natural pollinators can reduce apple production.

(ii) The parameters in the experiment are:

• Independent variable: Type of pollination method used, natural pollination or beekeeping.

• Dependent variables: Fruit setting and fruit drop.

• Controlled variables: Apple variety, soil, water, climate, farming practices and orchard conditions.

(iii) In Place A, where only natural pollinators were allowed, fruit setting was lower and fruit drop was higher. This shows lower apple yield.

In Place B, where beekeeping was used, fruit setting was higher and fruit drop was lower. This shows better apple production.

(iv) From the data, we can infer that beekeeping improves pollination and increases apple yield. It is useful for farmers, especially in areas where natural pollinators are decreasing.

Reproduction How Life Continues Class 9 Solutions Science Exploration Chapter 11

Question 13. A student claims, “In humans, ovulation always happens on day 14 of the menstrual cycle”. Critically examine this claim and state whether the claim is correct or not. Give at least two reasons for your answer.

Answer: The claim is not fully correct.

Ovulation may occur around the middle of the menstrual cycle, but it does not always happen exactly on day 14. The length of the menstrual cycle can vary from person to person.

Also, factors such as stress, hormonal changes, health conditions, diet and lifestyle can change the timing of ovulation. So, ovulation may happen earlier or later than day 14.

Class 9 Science Chapter 11 Question Answer (InText)

Think it Over (NCERT Textbook Page No. 208)

Question 1. When does a farmer prefer asexual or sexual methods of reproduction for crops production?

Answer: A farmer chooses the method of reproduction based on the crop and the desired result.

Asexual reproduction is preferred when the farmer wants plants with the same desirable qualities as the parent plant. It is useful for quick and uniform production. Examples include sugarcane, potato and banana.

Sexual reproduction is preferred when the farmer wants variation in plants. This helps in developing new varieties and improving adaptability. Crops such as wheat, rice and maize are commonly grown from seeds.

Question 2. Why do you think most complex animals and flowering plants use sexual reproduction, while many simple organisms, like yeast and Hydra, mainly reproduce asexually?

Answer: Simple organisms like yeast and Hydra often reproduce asexually because it is quick, simple and does not require a partner. This helps them produce many offspring in a short time under favourable conditions.

Complex animals and flowering plants mostly use sexual reproduction because it produces genetic variation. This variation helps organisms adapt to changing environments and increases their chances of survival.

Think it Over (NCERT Textbook Page No. 211)

Question 3. Are there other methods of asexual reproduction in organisms?

Answer: Yes, organisms reproduce asexually in many ways.

Some common methods are:

• Binary fission: One organism divides into two, as in Amoeba.

• Multiple fission: One organism divides into many daughter cells, as in Plasmodium.

• Budding: A new individual grows as a bud, as in yeast and Hydra.

• Fragmentation: The body breaks into pieces, and each piece grows into a new organism, as in Spirogyra.

• Spore formation: Spores develop into new organisms under favourable conditions, as in Rhizopus.

• Regeneration: A body part can grow into a complete organism, as in Planaria.

Bridging Science and Society (NCERT Textbook Page No. 212)

Question 1. Do you know any fùngus that can degrade plastic?

Answer: Yes, some fungi are known to degrade certain types of plastic. For example, Aspergillus tubingensis can break down polyurethane plastic. Another fungus, Pestalotiopsis microspora, has also been studied for its ability to use plastic as a source of food under certain conditions.

Bridging Science and Society (NCERT Textbook Page No. 213)

Question 2. How many combinations of characters can gametes carry?

Answer: Gametes can carry many different combinations of characters. The number of possible combinations depends on the number of chromosome pairs.

The formula is:

Number of combinations = 2ⁿ

Here, n is the number of chromosome pairs.

For example, if an organism has 2 pairs of chromosomes, the number of combinations will be:

2² = 4

In humans, there are 23 pairs of chromosomes. So, the possible combinations are:

2²³ = 8,388,608

This large number of combinations is one reason why offspring show variation.

Bridging Science and Society (NCERT Textbook Page No. 214)

Question 3. Flowers also enhance the aesthetics of the plants as they are coloured and/or fragrant. How are these features of flowers useful for reproduction? (Page 214)

Answer: Bright colours and fragrance help flowers attract pollinators such as insects, birds and bats. These pollinators transfer pollen from one flower to another. This helps in pollination and supports reproduction in flowering plants.

Bridging Science and Society (NCERT Textbook Page No. 215)

Question 4. Can you guess the function of the most attractive part of a flower, the coloured petals?

Answer: The coloured petals attract pollinators. Their bright colours, shapes and fragrance help bring insects or birds to the flower. This increases the chances of pollination.

Bridging Science and Society (NCERT Textbook Page No. 216)

Question 5. What do you think will happen if pollination does not occur?

Answer: If pollination does not occur, pollen will not reach the stigma. As a result, fertilisation will not take place. The ovule will not develop into a seed, and the ovary will not form a fruit. Therefore, reproduction in the plant will not be completed.

Pause and Ponder (NCERT Textbook Page No. 217) 

Question 1. In a China rose (Hibiscus or gudhal) plant, a pollen tube grows and continues through the style after pollen lands on the stigma. Which process is about to happen next?

Answer: The next process is fertilisation. The pollen tube carries the male gamete to the ovule, where it fuses with the female gamete to form a zygote.

Question 2. Look at the pictures (Fig. 11.16) of Calotropis (madar) seeds and dandelion seeds given below. Can you guess what kind of seed dispersal these seeds are adapted for?

Answer: Calotropis and dandelion seeds are adapted for wind dispersal. They are light and have hair-like structures that help them float in the air and travel to distant places.

Question 3. A farmer plants two varieties of maize side by side, but notices that seeds form only when pollen from one variety reaches the stigma of the other. What type of pollination is this?

Answer: This is cross-pollination. In this process, pollen from one plant is transferred to the stigma of another plant of the same species.

Pause and Ponder (NCERT Textbook Page No. 218) 

Question 4. Why do animals with external fertilisation generally produce more eggs than animals with internal fertilisation?

Answer: Animals with external fertilisation release eggs outside the body, usually in water. Since the eggs are exposed to predators, water currents and unfavourable surroundings, many of them may not survive.

Also, fertilisation outside the body is less certain. Therefore, these animals produce a large number of eggs to increase the chances that some eggs will be fertilised and develop into young ones.

In internal fertilisation, the embryo develops inside the female body, where it gets better protection. So, fewer eggs are produced compared to external fertilisation.

Question 5. In animals, which fertilisation method the gametes are more protected?

Answer: Gametes are more protected in internal fertilisation. This is because fertilisation takes place inside the female body, where the gametes and developing embryo are protected from external dangers.

Pause and Ponder (NCERT Textbook Page No. 222)

Question 6. Ravi suddenly notices that he is growing taller rapidly, his shoulders are broadening, and his voice cracks. What stage of life is he entering?

Answer: Ravi is entering adolescence, also called puberty. During this stage, the body undergoes rapid physical and hormonal changes, such as increase in height, broadening of shoulders and change in voice.

Question 7. Rina‘s period occurs every 28 days. Her last period was on the 5th of March. On which day is she most likely to get her next period?

Answer: Rina’s menstrual cycle is 28 days long. If her last period started on 5th March, her next period is likely to start after 28 days.

So, her next period will most likely begin around 2nd April.

Question 8. A human zygote is just formed. How many chromosomes does it have?

Answer: A human zygote has 46 chromosomes, arranged in 23 pairs. It receives 23 chromosomes from the mother’s egg and 23 chromosomes from the father’s sperm.

Pause and Ponder (NCERT Textbook Page No. 223)

Question 9. What protective devices can be used during sexual activity to reduce the spread of STIs?

Answer: Condoms can be used during sexual activity to reduce the spread of sexually transmitted infections, or STIs. They act as a barrier and help prevent the transfer of infection-causing microbes.

Question 10. If a couple uses oral contraceptive pills but not condoms, which risks remain and why?

Answer: If a couple uses oral contraceptive pills but not condoms, the risk of sexually transmitted infections (STIs) still remains.

Oral contraceptive pills help prevent pregnancy, but they do not protect against infections. Condoms are needed because they act as a barrier and reduce the spread of STIs.

Pause and Ponder (NCERT Textbook Page No. 224)

Question 11. In many animals, the young ones can walk or find food soon after birth, but human babies are completely dependent for a long time. What might be some advantages and disadvantages of this for humans as a species?

Answer: Human babies remain dependent on adults for a long time. This has both advantages and disadvantages.

Advantages:

• Babies receive care, food and protection from parents.

• They get more time for brain development.

• They learn language, behaviour and social skills slowly and properly.

Disadvantages:

• Human babies cannot survive alone.

• Parents need to spend a lot of time, energy and resources.

• Lack of care can affect the baby’s survival and development.

Thus, long-term dependence helps humans develop better learning and social abilities, but it also requires extended parental care.

Class 9 Science Chapter 11 Question Answer (Activities)

Activity 11.1: Let Us Explore (NCERT Textbook Page No. 209)

Aim: To study and observe the methods of vegetative propagation: cutting, grafting, and layering.

Observation: The three methods of vegetative propagation observed are cutting, grafting and layering.

Cutting: In cutting, a part of the plant, usually a stem, is cut and planted in soil. The lower leaves are removed before planting. With proper watering and care, roots grow from the nodes and a new plant develops. The new plant has the same characters as the parent plant.

Grafting: In grafting, a stem cutting from one plant is joined to a rooted plant of another related plant. A cut is made on the rooted plant, and the stem cutting is inserted into it. The joint is tied and covered properly. After some time, both parts join and grow as one plant.

Layering: In layering, a flexible branch is bent towards the soil and a part of it is covered with soil. After regular watering, roots grow from the buried part. Once roots develop properly, the branch is cut from the parent plant and grows as a new plant.

Conclusion: Cutting, grafting and layering are useful methods of vegetative propagation. These methods help produce new plants quickly from one parent plant while keeping the same desirable features. They are commonly used in agriculture and horticulture.

Activity 11.2: Let Us Explore (NCERT Textbook Page No. 211)

Aim: To study the process of budding in yeast under a compound microscope.

Observation: Under the microscope, small rounded outgrowths are seen on the parent yeast cells. These outgrowths are called buds. The nucleus divides, and one daughter nucleus enters the bud. The bud grows and later separates from the parent cell to form a new yeast cell.

Conclusion: Yeast reproduces asexually by budding. This method allows yeast to multiply quickly under favourable conditions. The new cells formed are genetically similar to the parent cell.

Activity 11.3: Let Us Experiment (NCERT Textbook Page No. 211-212)

Aim: To study the growth of mould on moist bread or roti.

Observations:

• A white cotton-like growth appears on moist bread or roti.

• Later, the growth may turn black or greenish.

• Under the microscope, thread-like structures called hyphae are seen.

• A network of hyphae forms the mycelium.

• Round sporangia are seen at the tips of the hyphae.

• Spores are present inside the sporangia.

Comparison: The observed mould resembles Rhizopus because it has spherical sporangia at the tips of hyphae. In Aspergillus, spores are arranged differently, usually in chains rather than inside closed sporangia.

Conclusion: Mould grows on moist bread or roti in warm and dark conditions. The spores present in air settle on the moist surface, germinate and form hyphae. This shows that fungi reproduce asexually through spores.

Activity 11.4: Let Us Explore (NCERT Textbook Page No. 213)

Aim: To understand how variation arises due to random combination of chromosomes.

Observation: Different combinations of bead colours are formed when one bead is randomly selected from each pair. Some combinations may repeat, while some may be new. With three pairs, eight different combinations can be formed.

This shows that when the number of chromosome pairs increases, the number of possible combinations in gametes also increases greatly.

Conclusion: Random mixing of chromosomes during reproduction produces different genetic combinations. This creates variation among organisms.

In humans, 23 pairs of chromosomes can produce a very large number of possible combinations. Such variation helps species adapt to changing environments and supports evolution.

Activity 11.5: Let Us Explore (NCERT Textbook Page No. 214-215)

Aim: To observe and identify the different parts of flowers and record their presence by studying various flowers from the surroundings.

Observation: Different parts of the flower such as sepals, petals, stamens and pistil are observed.

• Sepals are usually green and protect the flower bud.

• Petals are colourful and attract pollinators.

• Stamens have anther and filament. The anther produces pollen grains.

• The pistil has stigma, style and ovary.

• The ovary contains ovules.

Conclusion: Each part of a flower has a specific role in reproduction. Sepals protect the bud, petals attract pollinators, stamens produce pollen and the pistil contains the ovules. These parts help in pollination, fertilisation and seed formation.

Activity 11.6: Let Us Investigate (NCERT Textbook Page No. 215)

Aim: To study the role of pollination (self and cross pollination) in fruit formation by observing different conditions or treatments in flowers.

Table 11.2: Observation table to study pollination in a pea plant

Observation: The uncovered flower forms fruit normally. Covered flowers may show limited or no fruit formation if pollination does not occur. Flowers with removed stamens do not form fruits unless pollen is transferred from another source.

Conclusion: Pollination is necessary for fertilisation and fruit formation. Stamens are important because they produce pollen. Without pollen transfer, seed and fruit formation cannot take place.

Activity 11.7: Let Us Find Out (NCERT Textbook Page No. 217)

Aim: To compare different pollination strategies based on pollen production, seed formation, and their efficiency.

Table 11.3: Pollen production and seed formation data

Question 1. Compare and analyse the two strategies in terms of (Table 11.3)
Pollen to seed ratio
Efficiency of pollination and seed formation

Answer: In wind-pollinated plants, a very large number of pollen grains are released, but only a small number of seeds are formed. This gives a high pollen-to-seed ratio because many pollen grains are wasted.

In insect-pollinated plants, fewer pollen grains are produced, but more seeds are formed. This gives a lower pollen-to-seed ratio and shows better efficiency.

Wind pollination is less efficient because pollen is carried randomly by air. Insect pollination is more efficient because insects transfer pollen directly from one flower to another.

Question 2. Explain why producing a very large number of pollen grains can still be an effective pollination strategy.

Answer: Producing many pollen grains is useful in wind pollination because pollen transfer happens by chance. Many pollen grains may be lost in the air, but a few may still reach the stigma of the correct flower.

So, producing a large number of pollen grains increases the chances of successful pollination and seed formation.

Topics Covered in Class 9 Science Chapter 11 Reproduction: How Life Continues

• Importance of reproduction for continuation of species

• Asexual reproduction – binary fission, multiple fission, budding, fragmentation, spore formation, and regeneration

• Vegetative propagation – cutting, grafting, and layering

• Sexual reproduction in flowering plants – parts of a flower

• Pollination – self-pollination and cross-pollination

• Fertilisation, seed formation, and seed dispersal

• Reproduction in animals – external and internal fertilisation

• Human reproductive system and puberty

• Menstrual cycle, fertilisation, and development of the embryo

• Reproductive health and prevention of STIs

Advantages of Vedantu’s NCERT Solutions for Class 9 Science Chapter 11

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CBSE Class 9 Science Chapter 11 Reproduction: How Life Continues Study Materials

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