Question

the senate can approve or reject treaties that the president has worked out with other nations. which arrow stands for this check?

Explanation:

The problem is about the U.S. government's system of checks and balances, specifically the Senate (part of the Legislative branch) checking the Executive branch (president) on treaties. In the diagram, the arrow from Legislative to Executive (or the arrow representing Legislative's check on Executive for treaties) would be the one. Assuming the diagram has Legislative, Executive, and Judicial circles, the arrow from Legislative (where Senate is) to Executive (president) for treaty approval/rejection is the relevant check.

Answer:

(Assuming the diagram has Legislative (e.g., labeled "Legislative") to Executive arrow for this check, the answer would be the arrow from Legislative to Executive. If specific labels were like: suppose the bottom left is Legislative, top is Executive, bottom right is Judicial, then the arrow from Legislative to Executive for this treaty check. Since the exact diagram's arrow labels aren't fully visible, but conceptually, the arrow representing Legislative (Senate) checking Executive (president) on treaties is the one. If we assume the diagram has Legislative (let's say the left circle) to Executive (top circle) arrow for this, then that arrow. For example, if options were arrows: the arrow from Legislative (Senate's branch) to Executive (president's branch) for treaty approval/rejection.)