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Observe the figure given below… (Class 10 Science 2026, Q2)

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ScienceCBSE Class 10 · Board exam 2026, set 31/3/1 · 1 mark · MCQ

CBSE Class 10 Science 2026: question 2

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section A, question 2, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q2 · 1 mark · MCQCompetency-basedLife Processes

Observe the figure given below and identify the incorrect step for the activity set-up :

  1. (A)Both plants are kept in the dark room for three days before placing them in separate glass jars.
  2. (B)Both plants are covered with separate wooden bell-jars.
  3. (C)Use vaseline to seal the bottom of the jars with the glass plates.
  4. (D)Both potted plants were kept in sunlight for a few hours before the iodine test for the presence of starch.

Figure in the paper: Two potted plants (I) and (II), each covered by a bell-jar. In set-up (I) a watch-glass containing potassium hydroxide is placed beside the pot inside the bell-jar; set-up (II) has no watch-glass. 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

What must reach the leaves for photosynthesis to occur?

Hint 2

Can light pass through wood?

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. The experiment showing that CO is needed for photosynthesis requires light to reach the leaves. The bell-jars must therefore be transparent glass jars.

  2. Wooden bell-jars block sunlight, so no photosynthesis can occur in either plant. This is the incorrect step. Option (B).

    1 mark

Answer: (B)

Where the marks are

  • Identifies the wooden bell-jars as the wrong step (1 mark)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, 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.