Question

congress can change which federal courts get to decide which cases. which arrow stands for this check?

Explanation:

The question is about the separation of powers and checks and balances in the US government. Congress (Legislative branch) checking the Judicial branch (federal courts) by changing case jurisdiction. So the arrow from Legislative to Judicial (or the arrow where Legislative acts on Judicial) is the one. Looking at the diagram, the arrow from Legislative to Judicial (the one going from Legislative circle to Judicial circle) represents this check, as Congress (Legislative) influences the Judicial branch's case - deciding authority.

Answer:

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