Here's why:
* Viviparity is a diverse trait: It has evolved independently in many different animal groups, from mammals to fish to reptiles.
* New discoveries are made constantly: New species of animals are being discovered all the time, and some of these may turn out to be viviparous.
However, I can provide a list of some well-known viviparous animal groups:
* Mammals: All mammals are viviparous. This includes humans, dogs, cats, whales, bats, etc.
* Some reptiles: Several species of lizards and snakes are viviparous.
* Some fish: Some species of fish, like the guppy and the molly, are viviparous.
* Some sharks: Some species of sharks are viviparous. Others are ovoviviparous, meaning they lay eggs that hatch inside the mother.
To learn more about viviparity in a specific animal group, you can search online or consult a reference book on animal biology.
Let me know if you have any other questions.