Chapter 30, Problem 2STP

Summary Introduction

Introduction:

The circadian rhythm of an organism is a natural internal function, which regulates the sleep wake cycles and other body functions, such as temperature changes, metabolic activity etc.

Answer to Problem 2STP

Correct answer:

Option (D).

Explanation of Solution

Explanation/justification for the correct answer:

Option (D) they have less extreme temperature changes than animals active during the day time. Nocturnal animals are those animals that are active in the night. The animals that are active in the day time are constantly exposed to the sun, which may cause more fluctuations in the body temperature, in the night, when the sun is not there, there are less chances of fluctuation in body temperature. Hence, the correct answer is option (D).

Explanation for incorrect answer:

Option (A) they have higher body temperature than animals active during day. Due to the constant exposure to sunlight, the animals which are active during the day have a high variations in average body temperature, but the overall temperature is similar. Hence, it is an incorrect answer.

Option (B) they have more extreme temperature changes as compared to the animals active during the day. The nocturnal animals have less changes in the body temperatures. Hence, it is an incorrect answer.

Option (C) they have lower body temperature than the animals active during the day. The nocturnal in nature also maintain their body temperature which is more or less similar to animals active during the day. Hence, it is an incorrect answer.