In astronomical usage, all atoms heavier than helium are referred to as__________.

In astronomical usage, all atoms heavier than helium are referred to as__________.
 
  A) metals
  B) Population I atoms
  C) halos
  D) dark matter

Question 2

__________is a graph of orbital velocity versus radius in the disk of a galaxy.
 
  A) A rotation curve
  B) A normal distribution
  C) The H-R diagram
  D) The light curve

Question 3

Identify a true statement about Population II stars.
 
  A) Most of them are post-main sequence stars.
  B) They are located in the disk component of the galaxy.
  C) Most of them follow elliptical orbits.
  D) They have higher metal content than Population I stars.

Question 4

Most recent studies suggest that the Sun is about _____ from the center of our Galaxy.
 
  A) 10.3 kiloparsecs
  B) 8.2 kiloparsecs
  C) 9.4 kiloparsecs
  D) 11.1 kiloparsecs