As a Sun-like main-sequence star exhausts hydrogen in its core, it next becomes

As a Sun-like main-sequence star exhausts hydrogen in its core, it next becomes
 
  a. a protostar.
  b. a red giant star.
  c. a white dwarf star.

Question 2

What type of galaxies do astronomers believe to be the most common?
 
  a. elliptical
  b. spiral
  c. irregular
  d. Astronomers have no idea which type of galaxy is most common.

Question 3

Why is a brown dwarf not considered a star?
 
  What will be an ideal response?

Question 4

What distance method is used to determine the distance to the most distant galaxies when only a redshift is measured?
 
  a. Hubble's law
  b. supernova observations
  c. period-luminosity relationship of variable stars
  d. parallax