The correct answer is true.
It is true that the hyperextension bends joint in the opposite direction as flexion.
Extension and flexion are examples of angular motions where by the two axes of joint are being brought together to each other.
At other joints they can have rotational motion which can occur, for example shoulder. Bending the elbow is an example of flexion or clenching a hand into a fist.
Extension describes movement which straightens the increase of an angle which i between the body parts. Neck and trunk has backward movement which is in the posterior direction.
For example when someone stands his or her knees they extend. The leg is moved backward when there is extension of a hip.
