Question

if something happens to the vice president, the president can pick a replacement. but congress can accept or reject this pick. which arrow stands for this check?

Explanation:

The president is part of the Executive branch and Congress is part of the Legislative branch. The Legislative branch (Congress) checking the Executive branch's (president's) pick for vice - president replacement is shown by an arrow from the Legislative to the Executive.

Answer:

The arrow from the "Legislative" circle to the "Executive" circle.