Question: Why do we need oxygen to live rather than other gases?

Iain Bethune answered on 17 Jun 2015:

The great thing about chemistry is that every element is slightly different and they do different things. It so happens that we are Carbon-based lifeforms, and organic chemistry (involving Carbon, Hydrogen and a few other elements) is what works for us. In order for the chemical reactions to function that release energy into our body by breaking down molecules like glucose, we need Oxygen.

Maybe somewhere else in the universe there is life based on other elements, maybe Silicon, maybe something completely different!