Ablood test used to determine the amount of protein in red blood cells that carries oxygen is

Dominance:

Dominance may be defined as the phenomena in which intra allelic genes are involved in the process. The dominant trait hides the expression of the recessive trait. The same alleles of the gene are involved in this expression. Two loci of the same gene are involved in the dominance.

Epistasis:

Epistasis may be defined as the phenomena in which inter allelic genes are involved in the process. The one gene modifies the expression of the other gene. Different gene are involved in this process. Four loci of two different genes are involved in the process of epistasis.