Final answer:
Fever and increased tolerance for cold raise the BMR, while aging, decreased muscle mass, and fasting decrease the BMR.
Step-by-step explanation:
The factors that raise the Basal Metabolic Rate (BMR) include fever and increased tolerance for cold. Fever can increase BMR as the body generates extra heat to fight off infection. Exposure to cold temperature also raises BMR to maintain the body's internal temperature. On the other hand, factors that reduce BMR include aging, which decreases BMR by about 2% per decade, decreased muscle mass, which results in a lower BMR, and fasting, which can dramatically reduce BMR by up to 30%.