What are the building blocks of proteins?

The basic building block of a protein is called an amino acid. There are 20 amino acids in the proteins you eat and in the proteins within your body, and they link together to form large protein molecules. The variety of ways they mix and match allows for the great diversity of proteins in nature. Understanding the structure of amino acids and how they relate to the proteins they create can help you appreciate how critical these nutrients are in your diet.

The answer would be b. it is a learned trait