No explanation is given for this question. Let's discuss the answer together.
53.
People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude
A
atmospheric $${O_2}$$ level is less and hence more RBCs are needed to absorb the required amount of $${O_2}$$ to survive
B
there is more UV radiation which enhances RBC production
C
people eat more nutritive food, therefore more RBCs are formed
D
people get pollution - free air to breathe and more oxygen is available
Answer :
atmospheric $${O_2}$$ level is less and hence more RBCs are needed to absorb the required amount of $${O_2}$$ to survive
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55.
The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show?
A
The food plants mature and die at the end of the rainy season
B
Its population growth curve is of $$J$$-type
C
The population of its predators increases enormously
D
$$S$$-shaped or sigmoid growth of this insect
Answer :
Its population growth curve is of $$J$$-type
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60.
Consider the following four conditions (i) - (iv) and select the correct pair of them as adaptation to environment in desert lizards. The conditions : (i) Burrowing in soil to escape high temperature (ii) Losing heat rapidly from the body during high temperature (iii) Bask in sun when temperature is low (iv) Insulating body due to thick fatty dermis