Final answer:
The president has the power to veto laws passed by Congress.
Step-by-step explanation:
A check and balance that the president has over Congress is the power to veto laws. When Congress passes a bill and sends it to the president, the president can choose to approve or veto the bill. If the president vetoes a bill, it goes back to Congress, where it can only become a law if two-thirds of both the House of Representatives and the Senate vote to override the veto.
Learn more about Checks and balances between the president and Congress