For the typical mammals, the following properties apply:
1) hair on the body
2) endothermic regulation (warm-blooded)
3) milk-producing glands
4) live birth of babies (except egg-laying monotremes)
The two main characteristics are giving birth to live young and being mammalian.
Mammals are warmblooded and reproduce. Mammals do not lay eggs with the exception of the platypus.
A fish is not a mammal or a reptile they have gills and live underwater plus they can not breath without water
How do you say Charateristics?
face
bacteria
peaceful
no tail
this is a good site
A vertebrate has a spine.
solid
liquid
one characteristic is that they have broad leaves
it has no characteristics of any kind