Methane sources on Mars

[The Valkyrie]

Thanks, it did!

Arent we a bit narrow minded to think that the way we live, die and decay will be the same process on different locations in the universe? It just so happens that we have evolved to breathe oxygen and expel carbon dioxide, and our plant system does this in reverse. Couldn't other forms of life (not necessarily human) breathe and expel different gasses. If we change the gases breathed and expelled, I am certain when we decay a different gas would be present.

IIRC, it's thought that life could be based on elements other than carbon, which share some similar characteristics (such as silicon). It would seem that such lifeform's metabolic and de-compositional processes would differ from those on Earth.

However, I note that we don't have any examples of non-carbon based life, and Mars formed from the same "stuff" that earth did, so we might expect that life could take a similar path. It's not a solid assumption, but it does give us things to actually go looking for.

This.

We have to base our science on what we know and have observed.

We can speculate but it's unlikely we'll know about the decomposition process of non carbon based lifeforms until we actually encounter them.