Can humans breathe normally in space as they can on Earth?

Question: Can humans breathe normally in space as they can on Earth?
- Keywords:
  breathe,
  earth,
  space
Asked by The Comet Killer! to Vinita, Charlie 🚀, Andrea on 14 Jun 2016.
- Andrea Boyd answered on 14 Jun 2016:
  
  In space, no.
  
  On the International Space Station, yes. It’s a bit like being in an air conditioned plane or a submarine. We have a full Environmental Control and Life Support System recycles carbon dioxide back into Oxygen so the air on ISS is pretty similar to the air on Earth.

Question: Can humans breathe normally in space as they can on Earth?