Consider the discussion among three students about a galaxy that appears red. Check (✓) the box of any of the students who are correct.
a. Student 1 says "Because there is mainly red light in this galaxy and no blue light, I think that only small, red stars formed in this galaxy and not any big blue ones."
b. Student 2 replies "I disagree; it's just that blue stars don't last very long. I think the blue stars that may have been there in the past have already evolved into red giants, so the galaxy looks red due to the light from all the red giants."
c. Student 3 says "Wait a minute; I think you're both wrong. I thought that both blue stars and red giants live short lives, so they should both be gone. I think all that's left are small red stars. So the galaxy appears red because it's full of a lot of old, red stars, not red giants."