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Choose the equation of… (Class 10 Science 2026, Q3)

questionbuddy.in/q/cbse-10-science-2026-31-5-1-q3-equation-reaction-correctly-represents-anaerobic

ScienceCBSE Class 10 · Board exam 2026, set 31/5/1 · 1 mark · MCQ

CBSE Class 10 Science 2026: question 3

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

Q3 · 1 mark · MCQLife Processes

Choose the equation of reaction that correctly represents anaerobic respiration in muscles :

  1. (A)
  2. (B)
  3. (C)
  4. (D)

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/5/1.

Hints

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

Hint 1

Ethanol and CO₂ are the products of anaerobic respiration in yeast.

Hint 2

What builds up in muscles and causes cramps after heavy exercise?

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. Glycolysis splits glucose into pyruvate in the cytoplasm without using oxygen.

  2. When oxygen is short in muscle cells, pyruvate is converted to lactic acid with release of energy. The build-up of lactic acid causes cramps. Answer: (D).

    1 mark

Answer: (D)

Where the marks are

  • Selects glucose → pyruvate → lactic acid + energy under lack of oxygen (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 31/5/1: 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.