Whose responsibility is it to offer suggestions on ways to improve things at work?

your supervisor is entitled to give you ideas or leads to improve your performance at work.

Explanation: in healthy organizations, immediate superiors or immediate supervisors are the ones that have to provide information so employees can have a better performance. Actually, working mates can help a lot to do better at work.

umm of course in fact ur getting your answer : )

i’m pretty sure it is the second