MICROANATOMY

Detailed explanation-1: -Endotherms, such as birds and mammals, use metabolic heat to maintain a stable internal temperature, often one different from the environment. Ectotherms, like lizards and snakes, do not use metabolic heat to maintain their body temperature but take on the temperature of the environment.

Detailed explanation-2: -Mammals are the only animals that have hair. It grows from the outer layer of the skin. A dense covering of hair is often called fur or wool and insulates.

Detailed explanation-3: -Mammals are warm-blooded or homeotherms that maintain a constant body temperature, irrespective of the temperature of the surroundings. They do so by regulating metabolic processes.