Write the general characters of the class Mammalia.

Explanation

1. The body is covered by hairs.
2. They have mammary glands.
3. They have two pairs of limbs adapted for walking, running, climbing. burrowing, swimming and flying.
4. The skin has sweat glands, scent glands and sebaceous glands.
5. Exoskeleton includes horny epidermal horns, spines, claws, nails, hooves and bony dermal plates.
6. They have thecodont, heterodont and diphyodont teeth.
7. External ears or pinnae are present.
8. Heart is four chambered with left systemic arch.
9. RBCs are non-nucleated.
10. They have metanephric kidneys and they are ureotelic.
11. They are homeothermic.
12. Sexes are separate and fertilization is internal e.g. Platypus, kangaroo, elephants and man.