ATP is your answer here :)
The lobes of the brain that receives input from the nose is called the olfactory lobes. They are the ones responsible in receiving the sense of smell. These lobes are responsible in sending signals in the brain in the process of sense of smell.
I believe that the term metabolic rate reflects the energy the body needs to perform only its most essential activities. It is the rate of energy expenditure per unit time by endothermic animals while at rest, or the amount of energy that a person need to maintain the body functions while at rest per unit time.
