Do you a group theoretical proof of the following result?:
Theorem: A (non trivial) divisible abelian group is not finitely generated.
The only proof I know uses the fundamental theorem of finitely generated abelian groups, mainly based on ring theory.
Hints:
1) An abelian divisible group cannot have maximal groups (or, more generally, finite index subgroups);
2) A f.g. abelian group always has maximal subgroups.