The vacuole i believe is the answer
The estimated daily basal metabolic rate for a man who weighs 150 lb is 1636 kcal.
Basal metabolic rate is the rate of energy expenditure per unit time by endothermic animals at rest. Metabolism comprises the processes that the body needs to function. It is the amount of energy per unit time that a person needs to keep the body functioning at rest. Any increase to the metabolic weight, such as exercise, will increase the basal metabolic rate.
according to my biology teacher it's true. so there you have it.