Final answer:
Disuse of the joints hampers blood flow, contributing to cartilage deterioration and joint stiffening, often associated with osteoarthritis.
Step-by-step explanation:
The student has asked, "Disuse of the joints _____ _______ which hastens stiffening." The correct answer to fill in the blanks from the choices provided is B. hampers blood flow. The rationale for this answer is well-explained when we consider the consequences of joint disuse, such as the weakening of muscles and other issues that can contribute to joint health deterioration such as osteoarthritis. When the cartilage at the ends of bones breaks down, which can be accelerated by disuse, it leads to pain and stiffness in the joints. Regular movement of the joint can help maintain the cartilage, but lack of use (disuse) can contribute to its deterioration, negatively affecting the joint's function and promoting stiffening.