What does a system of check and balances protect against?

Sarah is stressed about her upcoming exam, so she goes to the gym to work out and feels less stressed afterwards. shianne is also stressed about her exam, but she decides to budget extra time to study and hires a tutor, which makes her feel less stressed. both sarah and shianne are engaged in adaptation. learning . appraisal. coping.

Congress checks on the power of the presidency by overriding a presidential reversal or veto. debating the bill in both of the houses. making laws without presidential review. sending the bill back to several committees

Arecent challenge to the european union created by a member state is?