Answer:
the biceps brachii muscle.
Step-by-step explanation:
The muscle that contracts to bend the arm at the elbow is the biceps brachii muscle. The biceps brachii muscle is a two-headed muscle located in the upper arm, and its primary function is to flex the elbow and supinate the forearm. When the biceps muscle contracts, it pulls on the tendon attached to the forearm, which causes the forearm to move upward towards the shoulder, resulting in a bending motion at the elbow joint. The biceps brachii muscle is commonly referred to as the "biceps" and is responsible for many everyday movements, such as lifting objects, pushing and pulling, and performing other manual tasks.