Although They are Mammals, Monotremes Lack

Question

Although they are mammals, monotremes lack
A) nipples.
B) ovaries in females.
C) hair.
D) mammary glands.
E) a four- chambered heart.

Accepted Answer

Monotremes, such as the platypus and echidna, are unique among mammals because they lay eggs and lack nipples. Instead, they secrete milk through openings in the skin.