Skip to main content
Super TutorResources
Chapter 11 of 13
QuestionsNotesFlashcardsSummaryFormulasQuizConceptsSyllabusPlan
NCERT Solutions

Reproduction : How Life Continues

CBSE · Class 9 · Science

NCERT Solutions for Reproduction : How Life Continues — CBSE Class 9 Science.

97 questions96 flashcards5 concepts

Interactive on Super Tutor

Studying Reproduction : How Life Continues? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for ncert solutions and more.

Try Super Tutor — Free

1,000+ Class 9 students started this chapter today

A diagram illustrating a transverse wave, such as ripples on a water surface, showing particles oscillating perpendicular to the direction of wave propagation.
Super Tutor

Learn better with visuals Super Tutor has hundreds of illustrations like this across every chapter — all free to try.

Get started
110 Questions Solved · 22 Sections

55 worked solutions below. Unlock all 110 free in Super Tutor

Think It Over

1When does a farmer prefer asexual or sexual methods of reproduction for crops production?Show solution
A farmer prefers asexual reproduction when he wants many genetically identical plants quickly, such as through cutting, grafting, layering, vegetative propagation or tissue culture. It is useful for large-scale propagation of desirable crops and for keeping the same useful traits. He prefers sexual reproduction when he wants variation and the development of new varieties through seeds, especially in plant breeding.

Not sure why a step works? check your working in Super Tutor

2Why do you think most complex animals and flowering plants use sexual reproduction, while many simple organisms, like yeast and hydra mainly reproduce asexually?Show solution
Most complex animals and flowering plants use sexual reproduction because it creates variation in offspring. This variation helps species adapt to changing environments and survive over generations. Many simple organisms like yeast and hydra mainly reproduce asexually because it is faster, needs only one parent, and helps them increase their number quickly when conditions are favourable.

Not sure why a step works? check your working in Super Tutor

Activity 11.1: Let us explore

1Interact with gardeners working in your school garden or farmers working in a field.Show solution

Not sure why a step works? check your working in Super Tutor

2Observe the techniques of cutting, grafting and layering followed by them. Discuss these techniques with them and record your observations in your notebook.Show solution

Not sure why a step works? check your working in Super Tutor

1(i)Does the gardener, scientist or horticulturist cut the overgrown branches of a plant at the end of its growing season? (Different plants have different growing seasons).Show solution
In cutting, the gardener may cut the overgrown branches or shoots of a plant at the end of its growing season and use them to prepare new plants. So the correct response is Yes.

Not sure why a step works? check your working in Super Tutor

1(ii)Observe them prepare the cuttings from a plant for the purpose of growing new plants. Note the average length of the cuttings.Show solution
The cuttings are usually prepared as short shoot pieces. The chapter says to observe the average length of the cuttings and notes that they are inserted about half their length into the soil. So the cutting is generally a small stem piece with nodes and internodes, long enough to plant easily and allow roots to develop.

Not sure why a step works? check your working in Super Tutor

1(iii)Count the number of nodes and internodes on the cuttings.Show solution
The chapter does not give one fixed number. The number of nodes and internodes on cuttings depends on the plant and the cutting taken. Students are asked to count them by observation.

Not sure why a step works? check your working in Super Tutor

2Collect the cuttings of the shoots in the morning for planting.Show solution

Not sure why a step works? check your working in Super Tutor

3Remove leaves from the lower half of each cutting.Show solution

Not sure why a step works? check your working in Super Tutor

4Insert the cuttings up to approximately half of their length in the soil mixed with compost at an angle of about 45−60∘45 - 60^{\circ} from the soil surface (Fig. 11.2).Show solution

Not sure why a step works? check your working in Super Tutor

5Water them regularly and observe the change, if any.Show solution

Not sure why a step works? check your working in Super Tutor

1(i)Does the gardener, scientist or horticulturist cut the overgrown branches of a plant at the end of its growing season?Show solution
Yes. In the cutting method, the overgrown branches of a plant may be cut at the end of its growing season to prepare cuttings for growing new plants.

Not sure why a step works? check your working in Super Tutor

Grafting

1For grafting, take a healthy rooted plant (Plant A) (Fig. 11.3a) (for example, a wild rose variety) and a healthy stem piece from another plant (Plant B) of other varieties (for example, a yellow rose plant and/or a pink rose plant) (Fig. 11.3c and Fig. 11.3d).Show solution

Not sure why a step works? check your working in Super Tutor

2Create a wound or a slit on a twig of Plant A (Fig. 11.3b).Show solution

Not sure why a step works? check your working in Super Tutor

3Insert and fit the cutting of stem of Plant B into the slit of stem of Plant A (Fig. 11.3e).Show solution

Not sure why a step works? check your working in Super Tutor

4Protect the wound or slit by using a cotton cloth or by wrapping film to avoid pests entering the graft until it heals (Fig. 11.3f). Cut the other branches of Plant A.Show solution

Not sure why a step works? check your working in Super Tutor

5Water the plant regularly and observe the growth of Plant B along with Plant A.Show solution

Not sure why a step works? check your working in Super Tutor

Layering

1For layering, select a flexible, thin twig of a tree or a shrub, such as a lemon and bury the middle part of the twig under the soil surface (Fig. 11.4).Show solution

Not sure why a step works? check your working in Super Tutor

2Water it regularly and observe the growth of new leaves on the twig buried in the soil.Show solution

Not sure why a step works? check your working in Super Tutor

3After 10–15 days, the roots will develop from the area of the twig buried in the soil.Show solution

Not sure why a step works? check your working in Super Tutor

4Once roots have developed, cut the twig from the parent plant, so that it can grow as a new plant.Show solution

Not sure why a step works? check your working in Super Tutor

Activity 11.2: Let us explore

1Take 20 mL20~\mathrm{mL} of sugar solution (1 g in 10 mL10~\mathrm{mL}) in a test tube.Show solution

Not sure why a step works? check your working in Super Tutor

2Add a pinch of yeast granules to it and then place a cotton plug on the mouth of the test tube.Show solution

Not sure why a step works? check your working in Super Tutor

3Keep it undisturbed in a warm place to allow the yeast to become active.Show solution

Not sure why a step works? check your working in Super Tutor

4After 1-2 hours, place a small drop of the yeast mixture from the test tube onto a glass slide and mount it with a coverslip.Show solution

Not sure why a step works? check your working in Super Tutor

5Observe the slide under a compound microscope at different magnifications and draw a diagram of what you observe.Show solution

Not sure why a step works? check your working in Super Tutor

11.2Do you observe any small, round outgrowths (buds) emerging from the parent yeast cells as shown in Fig. 11.6? Do these features indicate that the yeast is duplicating? How do these observations help you in understanding reproduction in yeast?Show solution
Yes, small round buds can be seen emerging from the parent yeast cells. These buds show that yeast is reproducing by budding, which is an asexual mode of reproduction. The bud grows, enlarges, and then separates from the parent cell to form a new individual. These observations help us understand that yeast reproduces by forming a small outgrowth from the parent cell rather than by fusion of gametes.

Not sure why a step works? check your working in Super Tutor

Activity 11.3: Let us experiment

1Take a small slice of bread or a roti and lightly moisten it with a few drops of water.Show solution

Not sure why a step works? check your working in Super Tutor

2Prepare a moist chamber using a plastic box or steel dabba. Place a thin layer of cotton in it, cover it with tissue paper and moisten it with pre-boiled water. Put the slice of bread or roti on the wet cotton bed covered with tissue paper.Show solution

Not sure why a step works? check your working in Super Tutor

3Keep the moist chamber in a warm and dark place, away from direct sunlight (if the bread or roti starts drying, add a few drops of water to keep it moist).Show solution

Not sure why a step works? check your working in Super Tutor

4Observe the bread or roti every day for any changes. Record your observations without touching it directly.Show solution

Not sure why a step works? check your working in Super Tutor

5After three days, observe the surface of the bread or roti carefully using a magnifying glass. Do you notice the growth of mould?Show solution

Not sure why a step works? check your working in Super Tutor

6When enough mould grows and spreads on it, carefully take the box to the school laboratory.Show solution

Not sure why a step works? check your working in Super Tutor

7With the help of a needle, carefully transfer a little mould onto a microscope slide. Under the guidance of your teacher, add cotton blue stain — a coloured dye to help see it better.Show solution

Not sure why a step works? check your working in Super Tutor

8Observe the mould under the microscope and draw its diagram based on your observations.Show solution

Not sure why a step works? check your working in Super Tutor

9Compare the diagram you have drawn with Fig. 11.8 and share your observations with your classmates.Show solution

Not sure why a step works? check your working in Super Tutor

Activity 11.4: Let us explore

1Take three pairs of beads of different colours (Fig. 11.9), each pair representing two contrasting characters on different chromatids of different chromosomes, such as:Show solution

Not sure why a step works? check your working in Super Tutor

2Make a combination from it by randomly picking one bead from each pair.Show solution

Not sure why a step works? check your working in Super Tutor

3Write your combination as 'light green, light blue, light red'.Show solution
The required combination is formed by picking one bead from each pair as described in the activity. The example combination given in the chapter is light green, light blue, light red.

Not sure why a step works? check your working in Super Tutor

4How many combinations can you make with just these three pairs of characters? Each time you make a combination using beads, you will get either the same combination or a different one. With just three pairs of characters, eight combinations are possible.Show solution
With three pairs of contrasting characters, each pair gives 2 choices. So the total combinations are:

2×2×2=82 \times 2 \times 2 = 8

So, 8 combinations are possible.

Not sure why a step works? check your working in Super Tutor

5Imagine how many combinations are possible with 23 pairs of chromosomes, each carrying genetic information for many characters.Show solution
With 23 pairs of chromosomes, each pair can contribute 2 possibilities, so the number of combinations becomes extremely large. The chapter only says to imagine how many combinations are possible and explains that this random mixing creates a unique combination in each person. So the answer is: an enormous number of combinations, far more than can be easily counted.

Not sure why a step works? check your working in Super Tutor

Activity 11.5: Let us explore

1Collect different types of flowers from your surroundings.Show solution

Not sure why a step works? check your working in Super Tutor

2Carefully observe each part of the flowers you have collected, starting from the outer whorl to the inner one.Show solution

Not sure why a step works? check your working in Super Tutor

3Record the presence of various floral parts in the different flowers that you collected in Table 11.1.Show solution
The observation table should show the presence or absence of floral parts in the flowers collected. A complete flower has sepals, petals, stamens and pistil. So students should record which of these parts are present in each flower, along with any other features they notice.

Not sure why a step works? check your working in Super Tutor

4Analyse the function of each part of the flower based on visible characters.Show solution
- Sepals: protect the flower in the bud stage.
- Petals: attract pollinators because they are usually coloured and/or fragrant.
- Stamen: the male part of the flower; its anther produces pollen grains containing male gametes.
- Pistil: the female part; it has stigma, style and ovary. The ovary contains ovules, and each ovule has an egg cell.

So, each part has a specific role in reproduction, especially in pollination and fertilisation.

Not sure why a step works? check your working in Super Tutor

5Cut a transverse and a longitudinal section of the ovary (swollen base of the pistil) and observe it under a dissecting microscope.Show solution

Not sure why a step works? check your working in Super Tutor

6Record any other feature(s) in Table 11.1.Show solution
Other features to record may include:

- whether the flower is complete or incomplete
- whether sepals and petals are fused or separate
- whether the stigma is flat or sticky
- whether the flower is coloured, fragrant, or has large petals
- the presence of ovary, ovules, anther, filament, style

These are features that can be seen while observing the flower and its sections.

Not sure why a step works? check your working in Super Tutor

7Draw a diagram of the structure you observed under the microscope.Show solution

Not sure why a step works? check your working in Super Tutor

Activity 11.6: Let us investigate

1Identify sweet pea (matar) or garden pea plants in a garden or a nearby field.Show solution

Not sure why a step works? check your working in Super Tutor

2Select two juvenile (less developed) flower bud and three freshly blossomed flowers on the same pea plant.Show solution

Not sure why a step works? check your working in Super Tutor

3Carefully remove the stamens from one of the two selected flowers buds and one of the three selected flowers.Show solution

Not sure why a step works? check your working in Super Tutor

4Take muslin cloth bags and loosely wrap them around the flower bud, the flower bud of which stamens are removed, the flower of which stamens are removed and a freshly blossomed flower (Fig. 11.12).Show solution

Not sure why a step works? check your working in Super Tutor

5Leave one freshly blossomed flower uncovered (without muslin cloth bag).Show solution

Not sure why a step works? check your working in Super Tutor

6Observe them regularly and notice the development of fruits in place of the flowers that were not covered with muslin cloth. Allow them to grow for a few more days.Show solution

Not sure why a step works? check your working in Super Tutor

7Once the pods are fully developed in the flowers without muslin cloth, remove the muslin cloth from all the wrapped flowers and observe them.Show solution

Not sure why a step works? check your working in Super Tutor

8Note your observations in Table 11.2.
9In which treatment(s) do you find the flowers are replaced by fruits?
10What can we infer from this activity?

Activity 11.7: Let us find out

1Compare and analyse the two strategies in terms of (Table 11.3)—
1(i)Pollen to seed ratio
1(ii)Efficiency of pollination and seed formation
2Explain why producing a very large number of pollen grains can still be an effective pollination strategy.

Pause and Ponder

1In 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?
2Look 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?
3A 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?
6Ravi suddenly notices that he is growing taller rapidly, his shoulders are broadening, and his voice cracks. What stage of life is he entering?
7Rina'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?
8A human zygote has just formed. How many chromosomes does it have?
9What protective devices can be used during sexual activity to reduce the spread of STIs?
10If a couple uses oral contraceptive pills but not condoms, which risks remain and why?
11In many animals, the young ones can walk or find food soon after birth but human babies are completely dependent on adults for a long time. What might be some advantages and disadvantages of this for humans as a species?

Revise, Reflect, Refine

1A 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?
2Arrange the following stages of sexual reproduction in plants in the correct order:
3Assertion (A): The zygote formed after fertilisation immediately attaches to the uterus wall.

Reason (R): The uterus wall is always prepared to receive the zygote.
4Why does asexual reproduction produce offsprings that are genetically identical to the parent?
5Explain why the menstrual cycle stops during pregnancy.
6Why are flowers that bloom at night white or light in colour as compared to flowers that bloom during the day?
7Why do vegetatively propagated plants tend to be more vulnerable to diseases than sexually reproduced plants?
8If all flowers in a type of plant were only capable of self-pollination, how would it affect the genetic diversity over several generations? Explain.
9A farmer wants to produce a large number of genetically identical plants quickly. Suggest suitable reproduction methods and explain why they are effective.
10Suresh prepares slides with pollen grains in different sugar concentrations (0%, 2.5%, 5%, 7.5%, 10%) to study the germination of pollen.
10(i)What are the different hypotheses which can be tested using this set-up?
10(ii)What parameters should be kept the same in this set-up?
11Look 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 —
12In 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
13A 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.
12(i)What are the hypotheses the researcher-farmers group has thought of for this investigation?
12(ii)What are the different parameters in the experiment?
12(iii)Compare and analyse the data of two experimental orchards Places A and B, in terms of high yields of apple fruits.
12(iv)Based on your analysis, what do you infer from the data?

The Journey Beyond

1Read about the 'Seed Village Programme' (Beej Gram Yojana) run by the Government of India. Why is it important to save indigenous seeds?
2Prepare a report on IVF, its uses and drawbacks. Discuss it with your class.
3Conduct a survey on crop fields. Interact with farmers on the crops grown on their farms and farm animals based on the following points
4Explore the crop fields near your school and find out different pollination strategies adopted by different cereal and vegetable crop plants. Talk to farmers on the following points —
5Observe the pollinators visiting your school garden. Notice and record their activity. Let each student take pictures of at least five different types of pollinators and which plants they visit. Compile the data and showcase your work to discuss how pollination occurs in different plants.
6Assist your elders in cutting fruits in the kitchen. While cutting fruits like lady finger, tomato, brinjal, capsicum, papaya, orange, muskmelon and more, make your observations based on the following and draw diagrams —
(i)When you cut a fruit longitudinally (Longitudinal Section: L.S.)
(ii)When you cut a fruit transversely (Transverse Section: T.S.)
(iii)Attachment of seeds
10Link your observations of the L.S. and T.S. of the fruit with the internal structure of the ovary of same species.

11.1 Asexual Reproduction

1How is vegetative propagation in plants helpful in agriculture?

11.2 Sexual Reproduction

1How does meiosis help create variations in sexual reproduction?

The Quest Continues ...

1Does a unicellular organism like amoeba or yeast ever ‘grow old’? When it divides, it produces almost two identical copies. So, does aging happen at all?

11.2.1 How does meiosis help create variations in sexual reproduction?

1How many combinations of characters can gametes carry?

11.2.3 How does the process of pollination occur in flowers?

1In the Activity 11.6, we stated that the process of pollination is the transfer of pollen to the stigma of a flower. The transfer of pollen occurs to the stigma of the same flower or another flower of the same plant, is called self-pollination (Fig. 11.13).
2If the pollen is transferred from the anther of a flower of one plant to the stigma of a flower of another plant of the same type, the pollination is called cross-pollination (Fig. 11.13).

11.2.4 Pollination strategies and reproductive success

1What do you think will happen if pollination does not occur?

11.3 Sexual Reproduction in Animals

1Study the information given in Table 11.4 for four categories of animals.

11.5.1 Reproductive maturity

1In this section, we will study how gametes form and meet, and how new life develops in human beings.

11.5.2 What are the parts of the male reproductive system?

1The scrotum keeps the testes slightly cooler than normal body temperature, which is necessary for sperm formation.

55 more solved questions in Reproduction : How Life Continues

Every remaining exercise is solved step by step in Super Tutor, plus practice quizzes and flashcards for this chapter. Free to start.

Stuck on a step?

Ask Super Tutor AI to explain any solution on this page in a simpler way — free, 24x7.

Ask a Doubt Free

Frequently Asked Questions

What are the important topics in Reproduction : How Life Continues for CBSE Class 9 Science?
Reproduction : How Life Continues covers several key topics that are frequently asked in CBSE Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Reproduction : How Life Continues — CBSE Class 9 Science?
Understand the core concepts first, then work through the 97 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
Where can I get free NCERT Solutions for Reproduction : How Life Continues Class 9 Science?
This page has free step-by-step NCERT Solutions for every exercise question in Reproduction : How Life Continues (CBSE Class 9 Science) — written the way examiners award marks: given, formula, working, answer.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Reproduction : How Life Continues

All 13 chapters — CBSE Class 9 Science NCERT Solutions

For serious students

Get the full Reproduction : How Life Continues chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for CBSE Class 9 Science.

Try Super Tutor Free
Try the full chapter — Free