oxygen

The Great Oxygenation Event may have happened all at once, around 2.3 billion years ago.

The oxygen levels declined at rates much faster than in oceans.

The work is now considered a basic aspect of how cells function.

Here's where our O2 really comes from.

It's physical, but it's psychological, too.

Leachates are toxic to the most numerous photosynthesizing organisms in the world.

A new study shows us why we may want to rethink how we search for extraterrestrial life.

A real breath of fresh air.

If you want to be a successful freediver, work out your spleen.

And climate change is to blame.