Cat, bat and rat belong to the class-Mammalia and have following common features:

● All have notochord at some stage of life cycle.

● All are warm-blooded animals.

● All have four-chambered heart.

● All have mammary glands for the production of milk to nourish their young.

● All have skin covered with hairs as well as sweat and oil glands.

● All respire through lungs.