55. When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both redandwhite-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
(A) The gene involved is on the X chromosome.
(B) The gene involved is on the Y chromosome.
(C) The gene involved is on an autosome.
(D) Other male-specific factors influence eye color in flies.
(E) Other female-specific factors influence eye color in flies.