Final answer:
The claim that skeletal muscles generate more free radicals at rest compared to during physical activity is false; more free radicals are produced during increased metabolic activities like exercise.
Step-by-step explanation:
The statement that skeletal muscles generate more free radicals during rest than during physical activity is false. During physical activity, the body's metabolic rate increases, leading to higher production of free radicals compared to when the body is at rest. When muscles contract and use energy, such as during exercise, they consume more oxygen and produce more free radicals as by-products of the metabolic processes necessary to generate ATP (adenosine triphosphate) for muscle contractions. Physical inactivity leads to muscle atrophy, which is characterized by a decrease in muscle cell size, number, and protein content, while muscle metabolism involves the generation of ATP through both aerobic and anaerobic pathways, with the former being the dominant source for resting or moderately active muscles.