Final answer:
The basal metabolic rate adjusts in response to caloric intake and body composition; decreases in calories, body weight, and lean body mass can lead to a lower BMR, depending on the specifics of each factor's change. The answer is option 2 and 3.
Step-by-step explanation:
The factors that influence the amount of energy expended via basal metabolic processes are complex and interconnected. Concerning the provided statements:
- If calories decrease, the body may reduce its basal metabolic rate (BMR) to conserve energy.
- If body weight decreases, particularly if the loss is from muscle mass, BMR may decrease because lean muscle is metabolically active and contributes to a higher metabolic rate.
- If lean body mass decreases, BMR definitely decreases as muscle tissue has a higher metabolic rate than fat tissue.
To summarize, the BMR adjusts as a response to changes in caloric intake and body composition to maintain homeostasis and support vital functions.
Hence, The answer is option 2 and 3.