2. The animal kingdom is divided in two major groups: Vertebrates and Invertebrates. The difference between them is that vertebrates have backbone and invertebrates haven’t it.

3. Vertebrates:
This type of animals is divided in : Mammals, Birds, Reptiles, Anphibians and Fishes.
Only the mammals are viviparous (their youngs born directly from their mother’s body). The rest,birds, reptiles,anphibians and fishes are oviparous (their youngs born from an egg).

4. Invertebrates:
This kind of animals haven’t got backbone. They are divided in 4 main groups:
Artrophods, that could be: Insects, Aracnids, Myriapods and Crustaceans.
Molluscs.
Equinoderms.
Anelids.