Characteristics features of mammals:

(a) Body is covered with hair.

(b) Skin is provided with sweat and sebaceous glands.

(c) Heart is four-chambered.

(d) Fertilization is internal.

(e) Females have mammary glands to produce milk to nourish their young ones.

(f) External ear-pinna, present.

(g) Eyes have eye lids.

(h) Warm-blooded.

(i) Respiration through lungs

(j) Body cavity divided’ into- thorax and abdomen by muscular diaphragm.