Basal Metabolic Rate is energy used at rest.

• A. Regulation of pH
• B. Measure of acidity or alkalinity
• C. Normal Blood pH
• D. Energy used at rest

Answer: (D)

Basal Metabolic Rate reflects the amount of energy the body needs to perform essential life-sustaining functions while at rest. It covers the energy cost of maintaining basic processes like breathing, circulating blood, sustaining heart activity, nerve signaling, and the steady work of cells to keep bodily systems running, all in a thermoneutral environment after a period of fasting. That’s why it’s described as energy used at rest.

The other options relate to acid-base balance rather than energy expenditure. Regulation of pH, a measure of acidity or alkalinity, and normal blood pH describe how the body manages acid–base status, not how much energy is used at rest.