Which of the Following is NOT an Essential Amino Acid

Question

Which of the following is NOT an essential amino acid?
A)leucine
B)valine
C)lysine
D)proline

Accepted Answer

Proline is a non-essential amino acid, meaning that the human body can produce it on its own and it is not necessary to obtain it through the diet. Leucine, valine, and lysine are all essential amino acids, meaning they must be obtained through the diet.