NEET BIOLOGY

Detailed explanation-1: -Animals that cannot generate internal heat are known as poikilotherms (poy-KIL-ah-therms), or cold-blooded animals. Insects, worms, fish, amphibians, and reptiles fall into this category-all creatures except mammals and birds.

Detailed explanation-2: -Cold-blooded animals do not maintain a constant body temperature. They get their heat from the outside environment, so their body temperature fluctuates, based on external temperatures.

Detailed explanation-3: -Animals, such as reptiles, fishes, and amphibians, that cannot control their body temperature and therefore become sluggish in cold weather.

Detailed explanation-4: -Birds apart from mammals are warm-blooded, which means that they can make their own body heat even when it is cold outside. Fishes, amphibians and reptiles all are cold-blooded animals. They can not control their body temperature and hence they become sluggish in the cold weather. Hence, option D is correct.

Detailed explanation-5: -Cold-blooded animals can be defined as animals that cannot regulate their internal body temperature with the change in the environment. They cannot survive in extreme temperature conditions. Examples of cold-blooded animals are reptiles, fish, etc.