Outstanding!
Just like their counterparts on land, aquatic plants generate oxygen during the process of photosynthesis. In fact, three-fourths of the earth’s oxygen supply is produced by phytoplankton in the oceans. (Special note: plants still use oxygen to turn food into energy, so they need it just like animals. But plants use much less than they produce while they're making their food during photosynthesis! If you'd like to learn more, check out the "Study Notes" for Dissolved Oxygen when you get back to the Student Lab.) Okay, you're ready for the next question!

Go to Question 2.