Among the following, which one lays eggs and does not produce young ones directly?

Answer: (a) Echidna

The echidna is a monotreme — a mammal that lays eggs (like the platypus).

The idea

A few mammals still lay eggs, as their reptile-like ancestors did. They are the monotremes: the platypus and the echidnas, found only in Australia and New Guinea. They are true mammals because they have fur and feed their young on milk.

Lays leathery eggs → Egg hatches → Mother has no teats; milk oozes from skin patches → Baby laps it up

Why the others are wrong

(b) Kangaroos are marsupials: tiny live young that grow in a pouch.

(c) Porcupines are placental mammals.

(d) Whales are placental mammals that give birth in water.

The trap

Kangaroo babies are born very small, so they feel “egg-like”. They are born alive.

Also know

The echidna is also called the spiny anteater. The platypus has a duck-like bill that senses the faint electric signals of its prey, and the male has a poisonous spur on its hind leg.