Why is "게가" not accepted ?
Perhaps marine biologists have already documented these crabs doing such.
What's the difference between 도와 and 도와줘 ?
돕다 - to aid, to assist, to help
도와주다 - to (give) help
Verbs ending in -주다 imply the action is being done for the benefit of someone else.
I recommend reading the tips and notes for Compound Verbs skill found on the mobile/desktop website.
Sorry for not making myself clear. I do understand the concept of compound verbs.
What I want to know is whether or when one form is preferred to the other?
From my limited experience 도와주다 is more common, which does not surprise me as helping is one of those verbs that usually involve doing something for the benefit of someone else.
게가 should be correct right?