A potted plant is kept horizontally for a considerable time. The three positions of the parts A and B of the potted plant are shown in the following figures: (a) Which figure shows the correct position taken by the parts A and B of the plant? (b) What type of phenomenon is exhibited by the figure that the correct position taken by the parts A and B of the plant shows ?

(a) The correct position taken by parts A and B is (ii). It is because: (i) The roots of plants always grow downward in response to gravity. This makes sure that they will find soil and water. (ii) The stems (or shoots) of plants always grow up, away from the pull of gravity. This makes sure that they will get light. (b) The type of phenomenon is geotropism.

Why is the use of iodised salt advisable?

Iodised salt contains iodine which stimulates the thyroid gland to produce thyroxine hormone. This hormone regulates the metabolism of fats, carbohydrates and protein in the body. Deficiency of iodine in our diet can lead to a condition called goitre, which is characterised by enlargement of the thyroid gland and swelling of the neck.

E M B I B E

Science for Tenth Class Part - 3 Biology>Chapter 2 - Control and Coordination>Short Answer Type Questions>Q 26

MEDIUM

10th CBSE

IMPORTANT

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Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.

Important Questions on Control and Coordination

MEDIUM

10th CBSE

IMPORTANT

Science for Tenth Class Part - 3 Biology>Chapter 2 - Control and Coordination>Short Answer Type Questions>Q 27

What is meant by nastic movements in plants? Give one example of nastic movements in plants.

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10th CBSE

IMPORTANT

Science for Tenth Class Part - 3 Biology>Chapter 2 - Control and Coordination>Short Answer Type Questions>Q 27

What is the difference between photonasty and thigmonasty?

MEDIUM

10th CBSE

IMPORTANT

Science for Tenth Class Part - 3 Biology>Chapter 2 - Control and Coordination>Short Answer Type Questions>Q 28

A potted plant is kept horizontally for a considerable time. The three positions of the parts A and B of the potted plant are shown in the following figures:
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