Final answer:
The degree to which an individual muscle will lengthen is referred to as flexibility, which is due to the muscle tissue's extensibility. Flexibility exercises help improve this attribute and prevent injuries. Hence, option (d) is correct.
Step-by-step explanation:
The degree to which an individual muscle will lengthen is referred to as flexibility. This quality of muscle tissue is due to its extensibility; the ability to stretch or extend beyond its normal length. Flexibility exercises, such as stretching, specifically target this aspect by improving the range of motion of muscles and joints, which can help prevent injuries related to physical activity. It's worth noting that muscle tissue can also recoil back to its original length when relaxed, thanks to its elasticity due to elastic fibers.
Thus, for the question at hand, the correct answer would be d) Flexibility. While exercise, in general, can improve muscular strength and muscular endurance, it is through flexibility exercises that a muscle’s extent of elongation can be increased. Aerobic exercises like running or cycling are more targeted towards boosting muscular endurance and cardiovascular health, whereas anaerobic exercises such as weight lifting focus on enhancing muscular strength.