Describe four factors that affect the metabolic rate of an active person. (pp. 408,411 )

Answer: Four factors that affect the metabolic rate of an active person are age, body size and composition, physical activity, and gender. Age affects metabolism as it tends to decrease with age due to factors like loss of muscle mass and hormonal changes. Body size and composition play a role as individuals with a larger body mass and higher percentage of lean muscle mass typically have a higher metabolic rate. Physical activity influences metabolism since more active individuals require more energy for their activities and high-intensity activities can significantly increase metabolic rate. Lastly, gender affects metabolism as men generally have a higher metabolic rate than women due to greater lean muscle mass, lower body fat percentage, and hormonal differences.