According to paragraph 1, what have scientists concluded from the fact that "some living protists are very like their ancestral forms"? A. The eye did not evolve until multicellular organisms arose. B. The ability to detect light and change behavior in response to light has existed for a long time. C. The ancestral forms of these living protists likely had an eyespot near the motile flagellum. D. The ancestral forms of these living protists depended primarily on light as the mechanism for modifying their metabolic activity or motility.