Question

Consider the following statements (A - D) and find out how many of them are correct related to regulation.

A. Sweating in humans during summer helps to bring down the body temperature.
B. Plants maintain a constant body temperature by transpiration.
C. Shivering during winter helps to generate heat.
D. Mammals can thrive in different climatic conditions due to their ability to maintain their body temperature.

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

The correct option is C Three

Maintenance of a constant internal environment (homeostasis), irrespective of the changes in the external environment, requires energy from metabolism. Based on whether they can maintain homeostasis or not, organisms can be classified as two types :

• Regulators are organisms that can maintain homeostasis. E.g., mammals and birds.
• Conformers are organisms that cannot maintain homeostasis. E.g., plants, amphibians, etc.

Mammals can maintain homeostasis by physiological as well as behavioural means. During summers, when the temperature rises, in mammals like humans, capillaries near the skin surface dilates to radiate heat, sweating and evaporation lowers the body temperature. Therefore, statement A is correct.


During winters, the environmental temperature is lower than the body temperature therefore, shivering helps in mechanical heat generation. This is done by inducing involuntary contraction of skeletal muscles and constriction of capillaries near skin which helps in heat retention and thereby increasing the temperature of the body. Therefore, statement C is correct.


Due to the above reasons, mammals are able to maintain their body temperature which provides them with an advantage and helps them to survive in different climatic conditions. Therefore, statement D is correct.

Plants are conformers, they cannot maintain a constant body temperature. Transpiration is the process by which plants lose water vapour through the stomata. This process can help in cooling down the plant during very hot summer days as the water evaporates by absorbing heat from the plant body. But it does not help in maintaining a constant body temperature. Therefore, statement B is incorrect.