In 1917 the biologist Thomas Hunt Morgan conducted studies in which he kept some caterpillars in the dark and placed some others under red, green, or blue lights. Exposure to red light produced butterflies with brightly colored wings. Exposure to green light resulted in dark-colored wings. Exposure to blue light or no light resulted in pale-colored wings. What was the most likely conclusion of Morgan’s research? A. The pigment in butterfly wings absorbs light from the environment.
B. Caterpillars exposed to red and green light are healthier than caterpillars exposed to no light or blue light.
C. The genes regulating wing color in butterflies are influenced by environmental factors.
D. The phenotypic expression of wing shape depends on color pigmentation in butterflies.