Question

Which is not characteristics of all mammals?

Answer 1

Answer:

b. giving birth to live young (viviparous)

Explanation:

Monotremes include duck-billed platypus and few other mammalian species that are oviparous. These mammalian species do not give birth to young ones, that is, they are not viviparous. Rather they lay eggs and are oviparous.

These species are also characterized by the absence of teeth. The primitive monotremes also exhibit external fertilization.

Examples of egg-laying mammals include anteaters or echidnas and the duck-billed platypus. The laid eggs are carried by females in an abdominal ouch to keep them warm.