Where does gas come from?

Question: Where does gas come from?

Asked by sciencegeekjade to Laura, Lily, Mark, Paul, Sarah on 24 Jun 2010 in Categories: General.
- Mark Roberts answered on 22 Jun 2010:
  
  Well it depends what kind of gas – do you mean the air or do you mean gas like methane that you use to cook / heat your house with?
  
  The latter comes from animals as they breakdown and degrade, part of the same process that produces oil.
  
  It is also produced by bacteria that live in our gut as well as the gut of animals such as cows.
- Lily Asquith answered on 22 Jun 2010:
  
  all sorts of different places…
- Sarah Bardsley answered on 23 Jun 2010:
  
  Its all about the state of matter. So we have solid, liquid, gas and also plasma. When molecules are separated and the matter expands to fill the space its in – it is a gas. A liquid can be converted into a gas by heating it up.
- Paul Roche answered on 24 Jun 2010:
  
  Matter normally comes in 3 states – solid, liquid and gas. The gas phase is the one where the particles have most freedom to move, and is usually formed when you heat up the liquid state to the boiling point of the material (e.g. 100 degrees for water).
  
  Infact, there are at least 2 other states of matter that they don’t tell you about in school – a plasma is something like a flame, and there is also a very complicated state called a Bose-Einstein Condensate, so next time your teacher tells you there are 3 states, you can correct them!

Question: Where does gas come from?