what are galaxies made of ?

Question: what are galaxies made of ?
- Keywords:
  galaxy,
  matter,
  universe
Asked by Legendary Marcin to Ryan on 25 Jun 2015.
- Ryan Cheale answered on 25 Jun 2015:
  
  Primordially hydrogen and helium because they were the first elements in existence, but they also have carbon monoxide and other elements all being churned up and around them!

Question: what are galaxies made of ?