Answer to Question 1
c
Answer to Question 2
According to Table 6-1, the major ones are age, height, growth, body composition (gender-specified), fever, stresses, environmental temperature, fasting/starvation, malnutrition, hormones (gender-specified), smoking, caffeine, and sleep. Here are five extracted directly from the text.
Gender. Women generally have a lower BMR than men, in large part because men typically have more lean body mass. In addition, menstrual hormones influence the BMR in women, raising it just prior to menstruation. Two sets of energy equationsone for men and one for womenwere developed to accommodate the influence of gender on energy expenditure.
Growth. The BMR is high in people who are growing. For this reason, pregnant and lactating women, infants, children, and adolescents have their own sets of energy equations.
Age. The BMR declines during adulthood as lean body mass diminishes. Physical activities tend to decline as well, bringing the average reduction in energy expenditure to about 5 percent per decade. The decline in the BMR that occurs when a person becomes less active reflects the loss of lean body mass and may be prevented with ongoing physical activity. Because age influences energy expenditure, it is also factored into the energy equations.
Physical activity. Using individual values for various physical activities is time consuming and impractical for estimating the energy needs of a population. Instead, various activities are clustered according to the typical intensity of a day's efforts.
Body composition and body size.
The BMR is high in people who are tall and so have a large surface area. Similarly, the more a person weighs, the more energy is expended on basal metabolism. For these reasons, the energy equations include a factor for both height and weight.