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In life there are certain… (Class 10 Science 2025, Q38)

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ScienceCBSE Class 10 · Board exam 2025, set 31/4/1 · 4 marks · Case-based

CBSE Class 10 Science 2025: question 38

Set in the CBSE Class 10 board exam of 2025, paper 31/4/1, section E, question 38, for 4 marks. Try it first; the hints and our step-by-step solution are below.

Q38 · 4 marks · Case-basedCompetency-basedControl and Coordination

In life there are certain changes in the environment called 'stimuli' to which we respond appropriately. Touching a flame suddenly is a dangerous situation for us. One way is to think consciously about the possibility of burning and then moving the hand. But our body has been designed in such a way that we save ourself from such situations immediately.

  1. (i)

    Name the action by which we protect ourself in the situation mentioned above and define it.

    1 mark
  2. (ii)

    Write the role of (a) motor and (b) relay neuron.

    1 mark
  3. (iii)(A)

    What are the two types of nervous system in human body? Name the components of each of them.

    2 marks

  4. OR

    (iii)(B)

    Which part of the human brain is responsible for : (a) thinking (b) picking up a pencil (c) controlling blood pressure (d) controlling hunger

    2 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/4/1.

Hints

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

Hint 1

Pulling the hand away from a flame happens before you even think about it; what is such an action called?

Hint 2

Follow the reflex arc: receptor → sensory neuron → ? → motor neuron → effector.

Hint 3

For (iii)(B), remember which jobs belong to the fore-brain, which to the cerebellum and which to the medulla.

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) Reflex action. It is a sudden, automatic and involuntary response to a stimulus in the environment, done without conscious thinking and controlled by the spinal cord.

    1 mark

  2. (ii)(a) Motor neuron: carries the message (impulse) from the spinal cord (CNS) to the effector organ, i.e. the muscle, which then moves the hand.

    ½ mark

  3. (ii)(b) Relay neuron: lies in the spinal cord and connects the sensory neuron to the motor neuron.

    ½ mark

  4. (iii)(A) Central nervous system (CNS): its components are the brain and the spinal cord.

    1 mark

  5. (iii)(A) Peripheral nervous system (PNS): its components are the cranial nerves (arising from the brain) and the spinal nerves (arising from the spinal cord).

    1 mark

  6. (iii)(B)(a) Thinking – fore-brain (cerebrum).

    ½ mark

  7. (iii)(B)(b) Picking up a pencil (precision of voluntary action) – cerebellum (hind-brain).

    ½ mark

  8. (iii)(B)(c) Controlling blood pressure – medulla (hind-brain).

    ½ mark

  9. (iii)(B)(d) Controlling hunger – fore-brain (it has a separate area for hunger).

    ½ mark

Answer: (i) Reflex action – a sudden, involuntary response to a stimulus; (ii)(a) Motor neuron carries the impulse from the spinal cord to the muscle; (b) Relay neuron links the sensory neuron to the motor neuron; (iii)(A) CNS – brain and spinal cord; PNS – cranial and spinal nerves; (iii)(B) (a) fore-brain/cerebrum, (b) cerebellum, (c) medulla, (d) fore-brain.

Where the marks are

  • Names reflex action (½ mark) and defines it (½ mark)
  • Role of motor neuron (½ mark)
  • Role of relay neuron (½ mark)
  • CNS with brain and spinal cord; PNS with cranial and spinal nerves (½ × 4 marks)
  • Correct brain part for each of the four functions (½ × 4 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 paper2025 board paper, set 31/4/1: 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.