Final answer:
The term for normal extensibility of soft tissues enabling full joint motion is flexibility. The correct answer is option a.
Step-by-step explanation:
The normal extensibility of soft tissues that allows for full range of motion of a joint is referred to as flexibility. Flexibility is important as it enables movements such as the ability to kick a soccer ball, pick up a fork, or dance. Prominent examples of joints with high flexibility are synovial joints, which, due to their structure and the presence of lubricating synovial fluid, provide greater mobility.
In contrast, joints with limited movement provide stability, such as those in the skull protecting the brain. The most flexible synovial joint is the ball-and-socket joint of the shoulder, which allows a very large range of motion due to minimal ligament support. On the contrary, the hip joint, also a ball-and-socket joint, has restricted movement due to strong ligaments providing stability during weight bearing.