Question

What characteristic is used to classify a mammal as a monotreme, marsupial or placental mammal?

• A. The environment in which it lives
• B. How much hair or fur it has
• C. The structure of its brain
• D. The way in which its young one's develop

Answer 1

The correct option is D The way in which its young one's develop

Mammals are classified as monotremes, marsupials or placental animals based on the pattern of development of their young. If they lay eggs, they are called monotremes. If they give birth to immature young ones that further develop in their pouches, they are called marsupials and if they give birth to mature young ones, they are called placental mammals.

So, the correct answer is 'The way in which its young one's develop'.