The sequence of amino acids in a protein is determined by DNA. In a protein that is present in all species, the amino acid sequence will be different. Once a protein has been chosen, the amino acid sequence of that protein in different species are compared. More similarities, or fewer differences, indicate that two species are closely related. (sorry if im wrong!)
Is there any optional answers?
Biological realm..............
When the nurse gives you a shot, the Vaccine release white blood cells that fights flu viruses, you can stay happy and healthy!
