__ are the building blocks of protein.

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.

Explanation:

Amino Acids

Explanation: There are 20 amino acids in the protein you eat and in the proteins within your body.They link together to form large protein molecules.

sex cells are usually half's then they find another half and make a fertilize egg