The macronutrient(s) whose main functions are to contribute the basic building blocks (amino acids) and to synthesize, grow, and maintain tissues in the body is/are .

Protein

Explanation:

This is because protein is a macronutrients and it is the building blocks which is important for building body mass and they are found through out the body, in the muscles, bones, skin, hair e.t.c

Protein can be gotten from both plants and animals.

The animal protein include meat, diary products, fishes e.t.c.

The plants protein include beans, r.t.c.