Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Hinge Joints In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure 38.28). Answer: hinge joint
Output:
The elbow is an example of a what type of joint?