In-text Questions — Nervous System — Control and Coordination

1. 12 marksNCERT Cl-10 Science, In-text Qs after §6.1.4, Q1

   What is the difference between a reflex action and walking?

   Hint. One of these needs a sudden trigger and bypasses conscious thought; the other is a continuously willed activity.

   Step 1 — Describe reflex action. A reflex action is a rapid, automatic, involuntary response to a specific stimulus, controlled at the level of the spinal cord itself so that it happens before the brain even processes the sensation.

   Step 2 — Describe walking. Walking is a voluntary action, consciously willed and coordinated by the brain, involving continuous fine control of posture and balance (via the cerebellum) even though it can feel automatic with practice.

   ✦ Answer: A reflex action is a fast, involuntary response to a sudden stimulus, handled by the spinal cord itself. Walking is a voluntary, consciously directed action, coordinated by the brain throughout.

   Where students slip. Calling walking 'involuntary' because it feels automatic once learned — it's still a consciously willed action coordinated by the brain, unlike a reflex, which specifically bypasses conscious control for speed.

2. 22 marksNCERT Cl-10 Science, In-text Qs after §6.1.4, Q2

   What happens at the synapse between two neurons?

   Hint. The electrical impulse doesn't literally jump the gap — something else carries the message across it.

   Step 1 — Recall what arrives at the synapse. An electrical impulse travels down the axon of the first neuron to its end.

   Step 2 — Describe what happens there. At the axon's end, the electrical impulse triggers the release of certain chemicals, which cross the synaptic gap.

   Step 3 — Describe what happens on the other side. These chemicals set off a new electrical impulse in the dendrite of the next neuron, since that's how the signal continues onward.

   ✦ Answer: At the synapse, the electrical impulse causes chemicals to be released; these chemicals cross the gap and trigger a fresh electrical impulse in the next neuron's dendrite.

   Where students slip. Saying the electrical impulse 'jumps across' the synapse directly — the impulse itself doesn't cross; a chemical signal does, which then restarts an electrical impulse on the other side.

3. 31 markNCERT Cl-10 Science, In-text Qs after §6.1.4, Q3

   Which part of the brain maintains posture and equilibrium of the body?

   Hint. This is the same part responsible for walking a straight line or riding a bicycle smoothly.

   Step 1 — Recall which brain region this is. The cerebellum, part of the hind-brain, is responsible for the precision of voluntary actions and for maintaining posture and balance, since that's the specific function this chapter assigns to it.

   ✦ Answer: The cerebellum.

   Where students slip. Naming the medulla — the medulla controls involuntary actions like blood pressure and salivation; posture and balance are the cerebellum's job.

4. 42 marksNCERT Cl-10 Science, In-text Qs after §6.1.4, Q4

   How do we detect the smell of an agarbatti (incense stick)?

   Hint. Trace the path from the nose's specialised receptors all the way to the part of the brain that interprets smell.

   Step 1 — Identify the receptor. Olfactory receptors in the nose detect the chemical particles released by the burning incense.

   Step 2 — Trace the signal. These receptors generate an electrical impulse, which travels via nerves to the fore-brain.

   Step 3 — Explain the final step. Since a specific area of the fore-brain is specialised for interpreting smell, it processes this impulse into the sensation we recognise as the agarbatti's scent.

   ✦ Answer: Olfactory receptors in the nose detect the incense's chemical particles, generating a nerve impulse that travels to a smell-specialised area of the fore-brain, where it's interpreted as that particular odour.

   Where students slip. Saying we 'taste' the incense through gustatory receptors — smell is detected specifically by olfactory receptors; gustatory receptors are for taste, a different sense entirely.

5. 52 marksNCERT Cl-10 Science, In-text Qs after §6.1.4, Q5

   What is the role of the brain in reflex action?

   Hint. The brain isn't in charge of the immediate response — but that doesn't mean it's left out of the loop entirely.

   Step 1 — Recall where the reflex arc is formed. Reflex arcs are formed in the spinal cord itself, so the response can happen quickly, without waiting for the brain to process it.

   Step 2 — State what the brain still does. Even so, the information about the stimulus also travels onward to reach the brain.

   Step 3 — Explain the consequence. This means the brain doesn't control the immediate reflex response, but it does register what happened afterwards — which is why we become aware of the pain only after our hand has already jerked back.

   ✦ Answer: The brain doesn't control the reflex itself (that happens in the spinal cord for speed), but it does receive the same information afterwards, which is why we become consciously aware of the stimulus only after the reflex has already occurred.

   Where students slip. Saying the brain has no role at all in reflex action — it just isn't involved in triggering the immediate response; it still receives the information and becomes aware of it afterwards.

Solutions written by the tuition.in editorial team and checked against the NCERT Class 10 Science textbook, Reprint 2026-27 (jesc106.pdf) — three in-text question sets (14 questions total) plus one end-of-chapter Exercise (12 questions). Unchanged by rationalisation, though the chapter examines the brain as fore-brain/mid-brain/hind-brain (never 'cerebrum') and covers only four plant hormones (auxin, gibberellins, cytokinins, abscisic acid — no ethylene) and six animal hormones (no glucagon or progesterone).. Questions are referenced from the NCERT textbook for identification.