Oxygen

Have you ever stopped to think where oxygen comes from? | Plankton, seaweed, and other photosynthesizers produce more than half of the world's oxygen. | Your first thought may be a rainforest, but here's a science fact for you: we can thank plant-based marine organisms for all that fresh air, according to the National Oceanic Service. | While we may know the answer to this question, scientists still can't explain these other ocean mysteries.