Question

Exclusively present in mammals

• A. Viviparity
• B. Pinna
• C. Homeothermy
• D. 4 chambered heart

Answer 1

The correct option is B Pinna

Class Mammalia shows following exclusive characteristics:

• They are warm-blooded animals.
• Show presence of hair on the body.
• Show presence of mammary glands to nurse young ones
• Show presence of external ear called pinna
• Except egg-laying mammals they are viviparous.
• Except egg-laying mammals a well-developed placenta is present.
• Show presence of sweat and sebaceous (oil) glands.
• They possess a muscular diaphragm dividing trunk into thorax and abdomen.

Presence of pinna (external ear) is an exclusive characteristic of mammals.