Question

flexor muscle (bending the arm) and which is the extensor muscle (straighten the arm).
in the pictures above, color in the flexor muscles red and the extensor muscles blue.

1. what joint did you use to lift the weight?
2. as you raised the weight the muscle was the flexor.
3. as you lowered the weight the muscle was the extensor.
4. when you lifted the weight which bone(s) did not move?
5. which bones(s) did move?

Explanation:

These questions relate to arm anatomy and movement. The elbow joint enables arm bending/straightening for weight lifting. The biceps act as the flexor when raising weight (bending the arm), and the triceps act as the extensor when lowering weight (controlling the straightening motion). The humerus (upper arm bone) stays fixed, while the radius and ulna (forearm bones) move during the lift.

Answer:

1. Elbow joint
2. Biceps
3. Triceps
4. Humerus (upper arm bone)
5. Radius and ulna (forearm bones)