The platypus is a mammal, specifically a monotreme.
Penguins belong to a vertebrate group called aves.
The mammal group to which the platypus belong is monotremata.There are only two animals in that group: the platypus and the echidna, and they are known as monotremes.
fish
They are amphibians
reptiles
reptiles
The apes
bird
reptile
The vertebrate group in which humans belong to is the mammal group.Humans belong to the Mammal group.
Sharks belong to the vertebrate group known as Fish. Specifically, they belong to the vertebrate group known as Chondrichthyes - all sharks and rays - which have skeletons of cartilage rather than bone.
mammals