Question

7. Where does oxygen come from in nature?

Answer 1

Most of Earth's oxygen comes from tiny ocean plants called phytoplankton that live near the water's surface and drift with the currents.

Step-by-step explanation:

Answer 2

Answer: Most of Earth's oxygen comes from tiny ocean plants – called phytoplankton – that live near the water's surface and drift with the currents. So, mostly from plants, trees etc...

Hope I helped!