The skeletons can be the same but have a different function, because they descended from a like ancestor. like a human arm and a bat's arm.
There’s many things that are not necessary. The things that are would be food water some sort of shelter and a working body, I think you can go from there. Sorry if that’s not what your looking for. Hope it helps though! ♥️
Answer:
Expiermenting and Researching
Explanation:
The process by which the body reacts to changes in order to keep conditions inside the body, for example temperature;
