Which of the following statements is incorrect?
a. the origin of the muscle is attached to the bone that does not move.
b. the insertion of the muscle is attached to the bone that moves.
c. when the muscle contracts, the insertion moves toward the origin.
d. all of the above are correct.

The correct answer is option D. all of the above are correct.

Explanation:

During muscle contraction, only one bone move and others remain stationary. The point or site where tendons are attached to the bone is known as origin and insertion. Insertion is the point where the muscle attached to the movable bone. Origin is the site or point where muscle binds to the immovable bones.

When muscle contracts the insertion moves towards the origin. For the example radius and ulna are movable bones and point where the muscle attaches to them are insertion and humerus and scapular are the bones that do not move and point where the muscle attaches to it is the origin.

Thus, the correct answer is option D. all of the above are correct.