What did edwin hubble discover about galaxies that allowed him to determine the expansion rate of the universe? a. the farther away a galaxy was, the less its light was shifted toward the red end of the spectrum. b. the farther away a galaxy was, the more its light was shifted toward the blue end of the spectrum. c. the farther away a galaxy was, the more its light was shifted toward the red end of the spectrum. d. the light from a galaxy was shifted a uniform amount toward the red end of the spectrum, regardless of its distance from earth.