Q3 of 36 Page 261

A. What does a stem do in response to gravity? What is this phenomenon known as?

B. What does a root do in response to light? What is this phenomenon known as?

(A) A stem grows in opposite direction to the stimulus of gravity, that is, gravitational force attracts the plant parts towards itself but the stem grows upwards, which means against the force of gravity. This is known as negative geotropism.

(B) The response of root towards light is in opposite direction,that is it grows downwards, towards the dark. Hence, the phenomenon is known as negative phototropism.


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Name the disease caused by the deficiency of insulin hormone in the body.

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A. What does a root do in response to gravity? What is this phenomenon known as?

B. What does a stem do in response to light? What is this phenomenon known as?

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A. What is a spinal cord? What is its main function?

B. Give the functions of medulla oblongata.

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A. Name the hormones secreted by the following endocrine glands:

(i) Thyroid gland


(ii) Parathyroid glands


(iii) Pancreas


(iv) Adrenal glands


B. Write the functions of testosterone and estrogen hormones.