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Class 10 Science Chapter 6: Control and Coordination MCQs with answers

10 multiple-choice questions on Control and Coordination, each with its answer and the reason, written from the NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter.

Question 1
A tea taster sips a cup and judges how sweet it is. The receptors on her tongue that respond to the sugar are
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Answer: (c) gustatory receptors

Gustatory receptors detect taste; olfactory receptors detect smell. Neurons that carry messages to muscles or within the spinal cord are not receptors.

Question 2
A small animal with very little of the complex neuron network needed for thinking steps on a sun-heated stone and pulls its leg back at once. It can respond so quickly because
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Answer: (a) the response runs through a reflex arc, which does not wait for the brain's thinking

Reflex arcs connect the nerves that detect heat directly to the nerves that move muscles. They evolved because thinking is not fast enough, and many animals have little or none of the network needed for thinking; muscles still need nerves, and receptors lie in the sense organs.

Question 3
In a single neuron, an electrical impulse travels in the order
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Answer: (d) dendrite → cell body → axon

Information picked up at the dendritic tip creates an impulse that travels from the dendrite to the cell body and then along the axon to its end.

Question 4
A toxin stops the axon endings of a neuron from releasing their chemicals, but leaves the neuron otherwise unharmed. The most direct result is that
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Answer: (b) no impulse is started in the dendrite of the next neuron

At the axon end the impulse releases chemicals which cross the synapse and start a similar impulse in the next neuron's dendrite. With no chemicals released, the impulse still reaches the axon end but goes no further.

Question 5
When Arjun kicks a football, impulses from a motor neuron make the muscles of his thigh contract. The impulse passes from the neuron to the muscle fibre at
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Answer: (d) the neuromuscular junction

Where a neuron meets a muscle, the axon's branched endings sit against the muscle fibre at the neuromuscular junction, a synapse through which the impulse reaches the muscle.

Question 6
Kabir touches a hot iron and jerks his hand away before he feels any pain. The connection that brings about this quick response is formed in the
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Answer: (a) spinal cord

Nerves that detect heat are connected directly to nerves that move muscles in a reflex arc, and reflex arcs are formed in the spinal cord itself.

Question 7
The withdrawal of a foot from a sharp nail does not wait for a conscious decision because
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Answer: (c) thinking involves many impulses through many neurons and would take too long

Thinking is a complex activity involving many nerve impulses from many neurons, so it is too slow; reflex arcs give the quick response. The information still goes on to the brain, so it is not true that the brain receives nothing or that the signal stops at the spinal cord.

Question 8
Which two together make up the central nervous system?
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Answer: (b) the brain and the spinal cord

The brain together with the spinal cord constitutes the central nervous system; the cranial and spinal nerves form the peripheral nervous system.

Question 9
After an injury to the back of the head, a patient has difficulty controlling his blood pressure and cannot stop frequent vomiting. The part of the brain most likely damaged is the
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Answer: (b) medulla

Involuntary actions including blood pressure, salivation and vomiting are controlled by the medulla in the hind-brain.

Question 10
After a large wedding lunch, Sunita feels that she cannot eat another bite. This sensation of being full comes from a centre in the
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Answer: (d) fore-brain

The sensation of feeling full comes from a centre associated with hunger, in a separate part of the fore-brain.

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