Answer:
The correct answer is D. reversibility
Step-by-step explanation:
Reversibility principle says that when a person goes an extended break from exercise his/her fitness level reverse or gets declined day by day because the muscle becomes weak and shrinks when it is unused.
Therefore when we take a long break from physical activity the fitness and skill level decline which we got from regular training but it can again be gained if the person resumes the workout regularly.
In a study is was observed that skill does not get decline easily and it requires a long time for skill to decline. Endurance, flexibility, strength and other components of physical fitness can easily decline over time. Therefore the right answer is D. reversibility.