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Observe the given diagram… (Class 10 Science 2026, Q16a)

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ScienceCBSE Class 10 · Board exam 2026, set 31/3/1 · 5 marks · Long answer

CBSE Class 10 Science 2026: question 16(a)

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section A, question 16(a), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q16(a) · 5 marks · Long answerCompetency-basedHow do Organisms Reproduce?

Observe the given diagram and answer the questions that follow :

  1. (i)

    Give the name of the structure and type of reproduction shown in the above diagram.

    0 marks
  2. (ii)

    State one advantage and one disadvantage of the above mentioned method of reproduction.

    0 marks
  3. (iii)

    Give reason : Asexual reproduction lacks genetic variation.

    0 marks
  4. (iv)

    Why have higher organisms resorted to sexual reproduction in spite of its complexity ?

    0 marks

Figure in the paper: A leaf with marginal notches; labels: Adventitious bud, Young Plant, Marginal notch, Leaf. Young plantlets are growing from the notches on the leaf margin. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/3/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

The leaf with buds in the notches on its margin is a well-known NCERT example.

Hint 2

Think about how many parents are involved and whether gametes fuse. What do two parents add that one cannot?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (i) Structure: Bryophyllum leaf, with buds in the notches on its margin.

    ½ mark

  2. Type: vegetative propagation, a form of asexual reproduction.

    ½ mark

  3. (ii) Advantage (any one): the new plants are genetically identical to the parent, so desirable traits are kept. They also flower and fruit earlier than seed-grown plants, and the method can raise plants that have lost the capacity to produce seeds.

    1 mark

  4. Disadvantage: there is no genetic variation, so all the plants can be harmed equally by a disease or by a change in the environment.

    1 mark

  5. (iii) Asexual reproduction involves only one parent and no fusion of gametes. The offspring form by mitosis and receive copies of the same DNA, so they have the same genetic make-up and show no variation.

    1 mark

  6. (iv) Sexual reproduction combines DNA from two parents, which creates genetic variation. Variation improves the chances of survival of the species in a changing environment and drives evolution.

    1 mark

Answer: (i) Bryophyllum leaf; vegetative propagation (asexual). (ii) Advantage: genetically identical plants / early flowering; Disadvantage: no variation. (iii) Single parent, no gamete fusion, mitotic division. (iv) It produces variation, which aids survival and evolution.

Where the marks are

  • Names Bryophyllum leaf (½ mark)
  • Names vegetative propagation / asexual reproduction (½ mark)
  • One correct advantage (1 mark)
  • Disadvantage: no genetic variation (1 mark)
  • Reason: single parent, no gamete fusion, offspring by mitosis (1 mark)
  • Sexual reproduction creates variation, aiding survival and evolution (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from How do Organisms Reproduce?, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/3/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.