Answer: Receptor protein.
Explanation:
The receptor protein on the cell surface would enable a cell to respond to glucagon. The glucagon binds to the GPCR on the liver and muscle cells and is known as glucagon receptor.
This receptor then stimulates cells to release glucose into the blood stream. Another hormones involved during this process is glucagon like peptide 1.
It works by binding to another GPCR which is GLP-1 receptor found on the pancreatic cells.
Natural selection is the only option that relates to the evolution theory
The answer is C barriers around mating
