Final answer:
Relative flexibility relates to the balance between joint mobility and stability, with synovial joints like the shoulder offering more mobility but less stability compared to the hip joint which is more stable but less mobile.
Step-by-step explanation:
The concept of relative flexibility pertains to the balance between the mobility and stability of joints in the body. While synovial joints are designed to allow for a wide range of movement, such as angular movements (flexion and extension) and rotational movement, there is a trade-off between how freely a joint can move and how stable it is. For example, a multiaxial ball-and-socket joint, like the shoulder, offers a large range of motion due to minimal ligament support, making it more mobile but less stable than other joints. In contrast, the hip joint's movement is restricted by strong ligaments, which reduce its range of motion, but help the joint provide stability during weight-bearing activities such as standing.