The answer is letter B.
The body is mostly composed of building blocks of proteins. These proteins are the major compounds of cells that reproduce in order to form new tissues. They are small parts of the cells that when bound together function in the growth, development, and healing stages of organisms. Protein can also be found as a source of nutrient taken from meat, poultry, and fish products. These are absorbed by the body and are used to fuel and provide energy to perform daily activities.