For now, life is flourishing on our oxygen-rich planet, but Earth wasn't always that way – and scientists have predicted that ...

However, photosynthesis doesn't just drive the carbon cycle — it also creates the oxygen necessary for respiring organisms. Interestingly, although green plants contribute much of the oxygen in ...

Sparse cultures of embryonic fibroblasts were synchronized in the G 0 portion of the cell cycle by serum starvation and then placed under either low (2.5%) or ambient (20%) oxygen for 24 hours.