Researchers investigate the transport of a certain protein into cells by endocytosis. In an experiment, the researchers incubate the cells in the presence of the protein and measure the amount of the protein that is absorbed into the cells over a five-minute period.

Based on their observations, what should the researchers do to further clarify how the availability of the protein outside the cells affects the rate of endocytosis of the protein?

A Incubate the cells in the absence of the protein.

B

Incubate the cells in the presence of several different proteins.

С

Incubate the cells in the presence of several different concentrations of the protein

Incubate the cells in the presence of the protein for several different lengths of time