If a very distant galaxy looks blue overall to astronomers, from this they can conclude that:
A) the galaxy is moving toward us at great speed
B) the galaxy must have a lot of young stars and thus active star formation must still be going in it
C) the galaxy must be composed mostly of very old stars
D) the galaxy must not be especially massive when compared to most galaxies
E) the galaxy must have had a personal tragedy of some sort and needs a lot of love

Question

Quizplus · Accepted Answer

The overall blue color of a galaxy suggests that new stars are being formed in it. Blue light has a shorter wavelength than other colors of light, which means it is emitted by hotter and more massive stars, often associated with star formation.

If a Very Distant Galaxy Looks Blue Overall to Astronomers