Cytochrome C is a protein that functions in cellular respiration as part of the electron transport chain. It is frequently used to determine evolutionary relationships between different organisms because it is highly conserved (only differs slightly) between different organisms. A student researching evolutionary relationships between different organisms performed an ELISA test to analyze differences between cytochrome C proteins in different organisms. What is the independent variable in this experiment?a) the organismb) the darkness of color resulting from the ELISA testc) the antibody used in the ELISA testd) the protein being compared (cytochrome C)