Just as grew close is the basic building block for carbohydrates, are the basic building blocks of protein

Just as glucose is the basic building block for carbohydrates, amino acids are the basic building blocks of protein. Amino acids contribute to the development of protein within the body and are vital in assisting in wound repair and encouraging healthy tissue in muscles, bones, skin and hair. There are 22 amino acids with 9 being essential.

i say that the answer is 'd'