Step-by-step explanation:
individuals contain genes that are unique to the individual. the genes are coded into mRNA and in the ribosomes the mRNA are read form tRNA to assemble amino acids and form a polypeptide chain which is modified further to form protein molecules. these proteins molecules form structures, enzymes and hormones which contribute to the individual's traits such as hair structures, digestive traits and body structures too.
therefore, proteins made off the genes in an individual determine their traits