AP BIOLOGY

Detailed explanation-1: -Fat provides the most energy of all the macronutrients, at a whopping 9 calories per gram.

Detailed explanation-2: -Most of the energy required by the human body is provided by carbohydrates and lipids; in fact, 30-70% of the energy used during rest comes from fat. As discussed previously, glucose is stored in the body as glycogen. While glycogen provides a ready source of energy, lipids primarily function as an energy reserve.

Detailed explanation-3: -Fats (lipids) A fat is made up of a glycerol, which is attached to 1 to 3 fatty acid chains. Most of the energy from fats comes from the many carbon bonds in these long, fatty acid chains. Fatty acids connect to glycerol in the region where each molecule has an-O-H group.

Detailed explanation-4: -Triglycerides yield more than twice the energy per unit mass when compared to carbohydrates and proteins.