Asource of energy that also serves as a carrier for certain vitamins is:

A source of energy that also serves as a carrier for certain vitamins is Fat. 
Vitamins falls into two categories that is fat soluble and water soluble. The fat soluble vitamins are A,D, E, and K. Being fat soluble means that they are absorbed in the lymph, are transported in the blood with carrier proteins, and they can be stored in the liver and fatty tissues. Fats is the body's most concentrated source of energy, providing more than twice as much potential energy as carbohydrate or protein. During exercise stored fat in the body are broken down to fatty acids.