Question

the primary duty of the legislative branch is to
enforce the laws for foreign nations
appoint all the supreme court justices
make federal laws for the united states

Explanation:

In a democratic - style government like that of the United States, the legislative branch's main function is law - making. It doesn't enforce laws for foreign nations (that's not its jurisdiction), and it doesn't appoint all Supreme Court justices (the executive branch nominates and the legislative branch confirms).

Answer:

make federal laws for the United States