What vertebrate group has three major groups egg-laying pouched and placental?

The vertebrate group that has three major groups: egg-laying, pouched, and placental is mammals.

* Egg-laying mammals (monotremes) like the platypus and echidna lay eggs.

* Pouched mammals (marsupials) like kangaroos and koalas give birth to relatively undeveloped young that complete their development in a pouch.

* Placental mammals like humans and dogs give birth to live young that have developed inside the mother's body, nourished through a placenta.