Q. Among the following sets of salient features, which set does not exclusively characterize mammals?
Answer:
Presence of mammary glands, sweat glands and diaphragm
Notes: The key characteristic features of mammals are the presence of placenta, skin with hairs, mammary gland, muscular diaphragm and giving birth young one. Aves are also worm blooded and their heart is four-chambered. Crocodiles (Reptilia) also have fourchambered heart.