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Which of the following… (Class 10 Science SQP 2025-26, Q2)

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ScienceCBSE Class 10 · Sample paper, session 2025-26 · 1 mark · MCQ

CBSE Class 10 Science sample paper 2025-26: question 2

From the official CBSE sample question paper for 2025-26, section A, question 2, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q2 · 1 mark · MCQLife Processes

Which of the following options indicates the products formed after breakdown of the glucose in our muscle cells when there is lack of oxygen?

  1. (A)Ethanol + carbon dioxide + Energy
  2. (B)Lactic acid + Energy
  3. (C)Lactic acid + carbon monoxide + Energy
  4. (D)Carbon dioxide + Water + Energy

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

Think about why your muscles cramp after a sprint.

Hint 2

Anaerobic respiration in yeast and in muscles gives different products.

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. In muscle cells, glucose is first broken down in the cytoplasm into pyruvate, which is a 3-carbon molecule.

  2. When oxygen is short, for example during hard exercise, pyruvate is converted into lactic acid. Only a small amount of energy is released. No CO is produced, so the products are lactic acid + energy: option (B). Ethanol + CO is what yeast produces.

    1 mark

Answer: Option (B): Lactic acid + Energy

Where the marks are

  • Identifies anaerobic respiration in muscle as giving lactic acid + energy, option (B) (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 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.