NCERT Solutions for Class 9 Science Exploration Chapter 11

Reproduction is the biological process by which living organisms produce new individuals of their own kind.
Asexual and sexual reproduction help life continue by producing offspring, transferring genetic information, and creating variation across generations.

NCERT Solutions for Class 9 Science Exploration Chapter 11 help students solve Reproduction: How Life Continues from the Class 9 Science textbook. This chapter explains asexual reproduction, vegetative propagation, budding, spore formation, sexual reproduction in plants and animals, pollination, fertilisation, human reproductive systems, menstrual cycle, pregnancy, contraception, and reproductive health. These NCERT Class 9 Science Solutions cover Pause and Ponder questions and all Class 9 Science Chapter 11 exercise solutions in a direct, exam-ready format.

Key Takeaways

• Reproduction: It ensures continuity of life by producing new individuals of the same species.
• Asexual reproduction: One parent produces genetically identical offspring called clones.
• Sexual reproduction: Two parents contribute genetic material, leading to variation.
• Human reproduction: Gametes are formed by meiosis, fertilisation forms a zygote, and pregnancy begins after implantation.

NCERT Solutions for Class 9 Science Exploration Chapter 11 Structure 2026

NCERT Solutions for Class 9 Science Exploration Chapter 11 In-Text Questions

Class 9 Science Exploration Chapter 11 uses examples from plants, fungi, animals, and humans to explain how life continues through reproduction.

Q1. Which process happens after a pollen tube grows through the style?

Question: In a china-rose plant, a pollen tube grows and continues through the style after pollen lands on the stigma. Which process is about to happen next?

Answer: Fertilisation is about to happen next.

Explanation:
After pollen lands on a compatible stigma, it germinates and forms a pollen tube. The male gamete travels through this pollen tube towards the ovule.

When the male gamete fuses with the egg cell inside the ovule, fertilisation takes place. This forms a zygote, which later develops into an embryo.

Q2. What kind of seed dispersal do calotropis and dandelion seeds show?

Answer: Calotropis and dandelion seeds are adapted for dispersal by wind.

Explanation:
Both seeds are light and have hair-like structures. These structures help them float in air and travel away from the parent plant.

Wind dispersal helps reduce competition between parent plant and young plants. It also helps the plant spread to new areas.

Q3. A farmer plants two maize varieties side by side. 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.

Explanation:
Cross-pollination occurs when pollen from the flower of one plant reaches the stigma of a flower on another plant of the same type.

Here, pollen moves from one variety of maize to another variety. Since two different plants are involved, the process is cross-pollination.

Q4. Why do animals with external fertilisation generally produce more eggs?

Answer: Animals with external fertilisation produce more eggs because the chances of survival of eggs and young ones are low.

Explanation:
In external fertilisation, eggs and sperm are released outside the body, usually in water. Many eggs may be eaten by other animals, washed away by currents, or fail to get fertilised.

Producing many eggs increases the chance that at least some young ones will survive.

Q5. In which fertilisation method are gametes more protected?

Answer: Gametes are more protected in internal fertilisation.

Explanation:
In internal fertilisation, sperm and egg meet inside the female body. This gives the gametes and developing embryo a safer environment.

In external fertilisation, gametes are released outside the body and are exposed to water currents, predators, and environmental changes.

Q6. Ravi notices rapid height growth, broadening shoulders, and voice cracking. What stage is he entering?

Answer: Ravi is entering puberty or adolescence.

Explanation:
During puberty, the reproductive organs mature and begin producing gametes. Boys may show rapid growth, broadening of shoulders, deepening or cracking of voice, and other physical changes.

This stage marks the beginning of reproductive maturity.

Q7. Rina’s period occurs every 28 days. Her last period was on 5 March. When is the next period likely?

Answer: Rina is most likely to get her next period on 2 April.

Explanation:
A 28-day menstrual cycle means the next period begins about 28 days after the previous one starts.

Counting 28 days from 5 March gives 2 April.

This is an estimate because menstrual cycles can vary naturally.

Q8. How many chromosomes does a human zygote have?

Answer: A human zygote has 46 chromosomes.

Explanation:
Human sperm has 23 chromosomes, and the egg also has 23 chromosomes.

During fertilisation:

$23 + 23 = 46$

So, the zygote has the normal diploid chromosome number of humans.

Q9. What protective devices can reduce the spread of STIs?

Answer: Condoms can reduce the spread of sexually transmitted infections.

Explanation:
Condoms act as barrier contraceptives. They reduce direct contact between body fluids during sexual activity.

This helps lower the risk of STIs such as gonorrhoea, syphilis, herpes, genital warts, HIV, and AIDS.

Q10. If a couple uses oral contraceptive pills but not condoms, which risks remain?

Answer: The risk of sexually transmitted infections remains.

Explanation:
Oral contraceptive pills help prevent pregnancy by affecting ovulation and hormones. However, they do not act as a physical barrier.

Condoms are needed to reduce STI transmission because they help prevent exchange of infected body fluids.

Q11. Why are human babies dependent on adults for a long time?

Answer: Human babies are dependent for a long time because their brain, body control, movement, feeding ability, and communication skills develop gradually after birth.

Explanation:
The long dependency period has both advantages and disadvantages.

Advantages:

1. Babies get protection and care from adults.
2. They get time to develop the brain and learn language, social behaviour, and skills.
3. Adults can pass knowledge and culture to the young ones.

Disadvantages:

1. Babies need continuous care and protection.
2. Parents and families must invest a lot of time, energy, and resources.
3. Young babies cannot survive alone for a long period.

This long care period supports learning and complex human development.

NCERT Solutions for Class 9 Science Exploration Chapter 11 Exercise Questions

The Revise, Reflect, Refine section includes questions on pollination, fertilisation, asexual reproduction, menstrual cycle, genetic diversity, plant propagation, and reproductive strategies.

Q1. Anthers are removed before maturity, then pollen from another plant is dusted on stigma. Which process is ensured?

Answer: The correct option is (ii) Cross-pollination.

Explanation:
Anthers are removed to prevent self-pollination. Pollen from another plant of the same species is then transferred to the stigma.

This ensures cross-pollination because pollen comes from a different plant.

Q2. Arrange the stages of sexual reproduction in plants.

Question: Arrange the following stages:
(i) Pollen germination on stigma
(ii) Fertilisation
(iii) Pollination
(iv) Formation of zygote

Answer: The correct order is:

1. Pollination
2. Pollen germination on stigma
3. Fertilisation
4. Formation of zygote

Explanation:
First, pollen grains reach the stigma. Then, the pollen grain germinates and forms a pollen tube.

The male gamete travels through the pollen tube and fuses with the egg. This fusion is fertilisation, and it forms the zygote.

Q3. Assertion and Reason on zygote and uterus wall

Question:
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.

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

Explanation:
The zygote does not immediately attach to the uterus wall. It first undergoes mitotic divisions while travelling towards the uterus.

The uterus lining becomes thick and rich in blood vessels to receive the developing zygote. However, this preparation occurs during the menstrual cycle and is not always present in the same condition.

A more accurate interpretation is that the assertion is false because implantation is not immediate.

Q4. Why does asexual reproduction produce genetically identical offspring?

Answer: Asexual reproduction produces genetically identical offspring because it involves only one parent and usually occurs through mitotic cell division.

Explanation:
In mitosis, daughter cells receive the same chromosome number and same genetic material as the parent cell.

Since there is no fusion of gametes and no mixing of genetic material from two parents, the offspring are almost exact copies of the parent. Such offspring are called clones.

Q5. Why does the menstrual cycle stop during pregnancy?

Answer: The menstrual cycle stops during pregnancy because the uterus lining is needed to nourish the developing embryo.

Explanation:
If fertilisation occurs, the zygote implants in the thick inner lining of the uterus. This lining is not shed because it supports the developing embryo.

Hormonal changes during pregnancy prevent ovulation and menstruation. So, periods stop during pregnancy.

Q6. Why are night-blooming flowers often white or light in colour?

Answer: Night-blooming flowers are often white or light-coloured because they are more visible in low light.

Explanation:
Many night-blooming flowers depend on nocturnal pollinators such as moths and some insects.

White or pale petals reflect limited moonlight or dim light and make the flower easier to locate. These flowers may also produce fragrance to attract pollinators at night.

Q7. Why are vegetatively propagated plants more vulnerable to diseases?

Answer: Vegetatively propagated plants are more vulnerable to diseases because they are genetically identical.

Explanation:
Vegetative propagation is a type of asexual reproduction. It produces clones with the same genetic material.

If one plant is susceptible to a disease, many or all plants of the same clone may also be susceptible. Sexual reproduction produces more variation, which can help some plants survive diseases.

Q8. What happens to genetic diversity if all flowers self-pollinate for many generations?

Answer: Genetic diversity will decrease over many generations.

Explanation:
Self-pollination uses pollen from the same flower or the same plant. This reduces mixing of genetic material from different plants.

Over time, offspring become more similar to the parent plant. This lowers variation and may reduce the ability of the plant population to adapt to changing conditions.

Q9. A farmer wants many genetically identical plants quickly. Suggest suitable methods.

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

Explanation:
These methods are effective because they produce new plants from vegetative parts of the parent plant. The offspring are genetically identical and preserve desirable traits.

Suitable methods:

1. Cutting: Useful for plants like rose, sugarcane, money plant, and hibiscus.
2. Grafting: Useful for fruit and ornamental plants.
3. Layering: Useful for plants with flexible branches.
4. Tissue culture: Useful for producing many healthy plantlets quickly, such as banana plants.

These methods save time and help farmers multiply useful varieties on a large scale.

Q10. Suresh studies pollen germination in different sugar concentrations.

Q10(i). What hypotheses can be tested?

Answer: Suresh can test how sugar concentration affects pollen germination and pollen tube growth.

Explanation:
Possible hypotheses:

1. Pollen grains germinate best at a particular sugar concentration.
2. Very low sugar concentration may reduce pollen germination.
3. Very high sugar concentration may reduce pollen germination.
4. Pollen tube length changes with sugar concentration.
5. A 5% or 7.5% sugar solution may support better pollen germination than 0% or 10%.

Q10(ii). What parameters should be kept the same?

Answer: All factors except sugar concentration should be kept the same.

Explanation:
Parameters to keep constant:

1. Type of pollen grains
2. Number of pollen grains on each slide
3. Volume of sugar solution
4. Temperature
5. Time allowed for germination
6. Microscope magnification
7. Slide preparation method
8. Humidity or moisture conditions

This makes the experiment fair and helps compare only the effect of sugar concentration.

Q11. Identify pollination type in tomato, wheat, and papaya.

Answer: Tomato usually shows self-pollination, wheat mainly shows wind pollination, and papaya usually shows cross-pollination.

Explanation:

Papaya depends on pollen transfer between different plants when male and female flowers occur on separate trees.

Q12. Apple orchards and beekeeping experiment

Q12(i). What hypotheses did the researcher-farmer group test?

Answer: They tested whether beekeeping increases pollination and fruit yield in apple orchards.

Explanation:
Possible hypotheses:

1. Apple orchards with more pollinators show higher fruit setting.
2. Mixed farming with beekeeping improves pollination.
3. Higher pollinator activity reduces fruit drop.
4. Decline in natural pollinators reduces apple yield.

Q12(ii). What are the different parameters in the experiment?

Answer: The main variable is pollination method, while fruit setting and fruit drop are measured outcomes.

Explanation:

Q12(iii). Compare the data of orchards at Places A and B.

Answer: Place B is expected to show higher fruit setting and lower fruit drop than Place A.

Explanation:
Beekeeping increases the number of pollinators visiting flowers. More pollinator visits improve pollen transfer between flowers.

This increases fruit setting and can reduce the number of developing fruits that drop early.

Q12(iv). What is the inference?

Answer: Beekeeping can improve apple yield by increasing pollination efficiency.

Explanation:
The data suggest that pollinator availability directly affects fruit production. If natural pollinators decline, managed pollination through beekeeping can help farmers improve apple fruit yield.

This also shows why pollinator conservation is important for agriculture.

Q13. Is ovulation always on day 14 of the menstrual cycle?

Answer: No, the claim is not always correct.

Explanation:
Ovulation often occurs around the middle of a 28-day cycle, but it does not always happen exactly on day 14.

Reasons:

1. Menstrual cycles vary from person to person. They may range from about 21 to 35 days.
2. Stress, health, nutrition, sleep, illness, and hormonal changes can affect ovulation timing.
3. Even in the same person, ovulation may shift from one cycle to another.
4. Day 14 is only an approximate estimate for a typical 28-day cycle.

So, saying that ovulation always happens on day 14 is inaccurate.

NCERT Solutions for Class 9 Science Exploration

Topics Covered in NCERT Solutions for Class 9 Science Exploration Chapter 11

Class 9 Science Exploration Chapter 11 covers reproduction in plants, animals, and humans. It explains how organisms produce new individuals and how variation is created.

• Reproduction How Life Continues Class 9
• Asexual reproduction Class 9
• Vegetative propagation Class 9
• Cutting, grafting, layering, and tissue culture
• Budding Class 9 Science
• Spore formation Class 9
• Clones and mitosis
• Sexual reproduction Class 9
• Meiosis and variation
• Chromosomes and gametes
• Flower as a reproductive organ
• Sepal, petal, stamen, and pistil
• Pollination and fertilisation Class 9
• Self pollination and cross pollination Class 9
• Pollination strategies in plants
• Seed and fruit formation
• External and internal fertilisation in animals
• Human reproductive system Class 9
• Male and female reproductive systems
• Gametogenesis
• Menstrual cycle Class 9
• Pregnancy and childbirth Class 9
• Contraception and reproductive health

Important Concepts in NCERT Solutions for Class 9 Science Exploration Chapter 11

Class 9 Science Chapter 11 solutions require a clear understanding of reproduction types, plant reproduction, human reproduction, and reproductive health.