All of these are much less common in the universe than oxygen though, which is the third most common element.

There are bacteria that can metabolise hydrogen gas, which is the most abundant element, but like all of these alternative metabolisms, it is much less efficient than oxygen-based systems. This might mean that simple bacterial life is common across the galaxy using lots of different biochemistries, but complex multicellular life only evolves where it has access to the boost in energy provided by oxygen reactions.

Luis Villazon