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Consider the following four statements (i-iv) about certain desert animals such as kangaroo-rat.
(i) They have dark colour and high rate of reproduction and excrete solid urine
(ii) They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs
(iii) They feed on dry seeds and do not require drinking water
(iv) They excrete very concentrated urine and do not use water to regulate body temperature
Out of these four, which two are correct -
(i) They have dark colour and high rate of reproduction and excrete solid urine
(ii) They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs
(iii) They feed on dry seeds and do not require drinking water
(iv) They excrete very concentrated urine and do not use water to regulate body temperature
Out of these four, which two are correct -
A
(iii) and (i)
B
(i) and (ii)
C
(iii) and (iv)
D
(ii) and (iii)
Detailed Solution
The kangaroo rat of the North American deserts is a classic example of adaptation to scarcity of water.
(iii) is correct: it feeds on dry seeds and does not need to drink water. It meets all its water requirements through the internal oxidation of fat, in which water is a by-product (metabolic water).
(iv) is correct: it has the ability to concentrate its urine, so that only a minimal volume of water is used to remove excretory products. It also does not use water for cooling the body (no sweating or panting); it avoids heat by staying in burrows during the day.
(i) is not correct: it is not dark coloured, and it excretes highly concentrated liquid urine, not solid urine.
(ii) is not correct: a covering of thick hairs and a slow breathing rate are not its adaptations for conserving water.
So the two correct statements are (iii) and (iv).
(iii) is correct: it feeds on dry seeds and does not need to drink water. It meets all its water requirements through the internal oxidation of fat, in which water is a by-product (metabolic water).
(iv) is correct: it has the ability to concentrate its urine, so that only a minimal volume of water is used to remove excretory products. It also does not use water for cooling the body (no sweating or panting); it avoids heat by staying in burrows during the day.
(i) is not correct: it is not dark coloured, and it excretes highly concentrated liquid urine, not solid urine.
(ii) is not correct: a covering of thick hairs and a slow breathing rate are not its adaptations for conserving water.
So the two correct statements are (iii) and (iv).