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Annie was conducting… (Class 10 Science SQP 2025-26, Q16B)

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ScienceCBSE Class 10 · Sample paper, session 2025-26 · 5 marks · Long answer

CBSE Class 10 Science sample paper 2025-26: question 16(B)

From the official CBSE sample question paper for 2025-26, section A, question 16(B), for 5 marks. Try it first; the hints and our step-by-step solution are below.

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

Annie was conducting research on the number of fruits produced by watermelon under different conditions. She grew 25 watermelon plants each in both glass house A and B. She introduced pollinators in glass house A only.

  1. (i)

    What difference will she observe in the number of fruits produced in the two glass houses? Explain with reason.

    3 marks
  2. (ii)

    List 3 changes that will occur in a flower once it gets fertilized.

    2 marks

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

Are watermelon flowers bisexual or unisexual?

Hint 2

Without bees, how would pollen reach a female flower?

Hint 3

After fertilisation, follow what happens to the ovule, the ovary and the remaining flower parts.

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) Glass house A, which has pollinators, will produce more fruits than glass house B.

    1 mark

  2. (i) Reason: watermelon has unisexual flowers, with male and female flowers separate. Pollen must be carried from a male flower to the stigma of a female flower.

    1 mark

  3. (i) Pollinators such as bees carry out this transfer (cross-pollination), so more female flowers are fertilised and more fruits form. In B there are no pollinators, and pollen rarely reaches a stigma, especially when the flowers are far apart. Fewer flowers are fertilised, so fewer fruits are produced.

    1 mark

  4. (ii) Change 1: the zygote develops into an embryo, and the ovule develops a tough coat and becomes a seed.

    ½ mark

  5. (ii) Change 2: the ovary grows and ripens to form the fruit.

    1 mark

  6. (ii) Change 3: the petals, sepals, stamens, style and stigma shrivel and fall off.

    ½ mark

Answer: (i) Glass house A gives more fruits; watermelon flowers are unisexual and need pollinators for pollen transfer, so B gives few fruits. (ii) Ovule → seed; ovary → fruit; petals, sepals, stamens, style and stigma shrivel and fall off.

Where the marks are

  • States that glass house A has more fruits than B (1 mark)
  • Notes watermelon flowers are unisexual, needing pollen transfer between flowers (1 mark)
  • Explains pollinators increase cross-pollination and fertilisation, while B has less (1 mark)
  • Lists three post-fertilisation changes: ovule to seed, ovary to fruit, other floral parts fall (2 marks)

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 paperSample paper 2025-26: 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.