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Given below are certain… (Class 10 Science 2026, Q16b)

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

CBSE Class 10 Science 2026: question 16(b)

Set in the CBSE Class 10 board exam of 2026, paper 31/1/1, 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?

Given below are certain situations. Analyse and describe what would happen when:

  1. (i)

    Spores are liberated from blob-like structures of the bread mould?

    0 marks
  2. (ii)

    Leaves of bryophyllum fall on wet soil?

    0 marks
  3. (iii)

    A pollen from different species land on the stigma of totally unrelated species?

    0 marks
  4. (iv)

    Copper-T is placed in the uterus of a human female?

    0 marks
  5. (v)

    Spirogyra breaks into smaller fragments upon maturation?

    0 marks

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

Hints

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

Hint 1

Each situation shows a reproduction method from the NCERT chapter.

Hint 2

For (iii), think about whether the pollen tube can grow.

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) The spores spread through the air. When they land on a suitable moist surface with the right temperature, each spore germinates and grows into a new Rhizopus (bread mould) plant.

    1 mark

  2. (ii) Buds in the notches along the leaf margin develop into new plantlets on the wet soil. This is vegetative propagation.

    1 mark

  3. (iii) The stigma of an unrelated species does not support the foreign pollen. No pollen tube forms, so fertilisation does not take place.

    1 mark

  4. (iv) The copper-T prevents fertilisation and implantation, so pregnancy is prevented. It is a contraceptive device.

    1 mark

  5. (v) Each fragment grows into a new Spirogyra filament. This is fragmentation, an asexual method.

    1 mark

Answer: (i) Spores germinate into new Rhizopus; (ii) leaf-notch buds grow into new plants; (iii) no pollen tube, no fertilisation; (iv) pregnancy prevented; (v) each fragment grows into a new individual.

Where the marks are

  • Spores develop into new Rhizopus under moist, warm conditions (1 mark)
  • New plants from buds in leaf notches (1 mark)
  • No pollen tube/fertilisation (1 mark)
  • Fertilisation/pregnancy prevented (1 mark)
  • Each fragment becomes a new organism (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 31/1/1: 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.