Ode to Oxygen Quiz

Where did oxygen atoms first form?

True or False? The first O2 molecules were made by bacteria.

Oxygen is the second most abundant element in the Earth. What’s the most abundant element?

What molecule(s) is (or are) broken down during photosynthesis to make O2 molecules and organic carbon?

Roughly how long did it take after Earth formed for O2 to build up in the atmosphere to modern levels (20%)?

We might be breathing some of the same air as the dinosaurs breathed.

Which came first, oxygen increasing in the atmosphere, or the evolution of animals?