Question

Presence of is a unique characteristic of mammals.

• A. mammary gland
• B. two pairs of limbs
• C. 4 chambered heart
• D. ovipary

Answer 1

The correct option is A mammary gland

Mammals are characterised by the presence of mammary glands, which produce milk. This helps them to nourish their young ones.
Ovipary is seen in birds and other lower animals too. Birds also have a 4 chambered heart and 2 pairs of limbs of which one pair is modified into wings.