Final answer:
The independent variable in the experiment involving cytochrome c and the determination of evolutionary relationships between organisms is the organism itself. Cytochrome c's highly conserved nature across species makes it an excellent marker for evolutionary studies.
Step-by-step explanation:
The independent variable is the factor that is changed or manipulated in an experiment to see its effects on the dependent variable. In this case, different organisms are being compared to analyze the cytochrome c sequence to determine evolutionary relationships.
Cytochrome c is a highly conserved protein that plays a crucial role in the electron transport chain of cellular respiration. It has a heme prosthetic group, which alternately reduces and oxidizes during electron transfer, contributing to the production of cellular energy. The conservation of cytochrome c is key for studying evolutionary kinship, as its sequence remains strikingly similar across different species. This similarity allows scientists to use it to compare the evolutionary distances between organisms. By analyzing the conservation level of cytochrome c among various species, insights into evolutionary timelines and relatedness can be derived.