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Read the following passage… (Class 10 Science 2026, Q15)

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ScienceCBSE Class 10 · Board exam 2026, set 31/2/1 · 4 marks · Case-based

CBSE Class 10 Science 2026: question 15

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, section A, question 15, for 4 marks. Try it first; the hints and our step-by-step solution are below.

Q15 · 4 marks · Case-basedCompetency-basedControl and Coordination

Read the following passage and answer the questions that follow :

A middle-aged person is facing some cognitive changes in himself. His early symptoms included mild forgetfulness. For example, forgetting where he left his mobile or failing to find words to complete his sentences. He was facing problems in driving a car, climbing up and down the stairs, inserting a plug into an outlet. He slowly developed a sad mood and anxiety.

  1. (a)

    What are voluntary actions ?

    1 mark
  2. (b)

    Which part of the brain is responsible for precision of voluntary actions ?

    1 mark
  3. (c)(i)

    Explain the role of the medulla.

    2 marks

  4. OR

    (c)(ii)

    How do the animal muscles move ?

    2 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/2/1.

Hints

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

Hint 1

Voluntary means 'by choice'.

Hint 2

The hindbrain has two parts named in NCERT: one for balance and precision, one for involuntary actions.

Hint 3

For muscle movement, think about what happens to special proteins inside muscle cells.

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. (a) Voluntary actions are actions that are under our control and done according to our will, such as writing or walking. They are controlled by the forebrain.

    1 mark

  2. (b) The cerebellum (in the hindbrain) is responsible for the precision of voluntary actions and for maintaining posture and balance.

    1 mark

  3. (c)(i) The medulla, in the hindbrain, controls involuntary actions such as heart rate, blood pressure and breathing. It also controls reflexes like sneezing and vomiting.

    2 marks

  4. (c)(ii) Animal muscle cells contain special proteins. In response to nerve electrical impulses, these proteins change both their shape and their arrangement in the cell. The new arrangement gives the muscle cells a shorter form, so the muscles contract and the animal moves.

    2 marks

Answer: (a) Actions under our will, controlled by the forebrain; (b) Cerebellum; (c)(i) Medulla controls involuntary actions like heartbeat, blood pressure, breathing, sneezing and vomiting; (c)(ii) Muscle proteins change shape and arrangement on nerve impulses, shortening the cells.

Where the marks are

  • Defines voluntary actions as those under our will or controlled by the forebrain (1 mark)
  • Names cerebellum (1 mark)
  • (c)(i) Medulla regulates involuntary functions with examples (2 marks)
  • (c)(ii) Muscle proteins change shape and arrangement in response to impulses, shortening the cells (2 marks)

Revise the chapter

Practise this chapterBoard-style questions from Control and Coordination, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/2/1: 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.