What is the difference between these skeletons?

Question

3D

Tell me what is the difference between the 2nd and 3rd skeletons (from left to right)? That is, why are bones visible on the 2nd skeleton, but not on the 3rd? Apparently on the 3rd skeleton only joints are visible. Though In Unity both that and that norms are imported.
Image Link:
Naked Skeleton
With Mesh
Thanks in advance

Answer 1

They are small, I understand. If you mean the bones of the arms and legs