Sea temperatures would decrease. Greenhouse gases would increase. Atmospheric oxygen would increase. Sea levels would drastically decrease.
I gave my students this multiple choice question: Phytoplankton are plant-like microscopic organisms that float in bodies of water such as the ocean. They take in carbon dioxide during the process of photosynthesis. What would most likely happen if the population of phytoplankton was destroyed?

Only one answer is correct among these 4 choices:
- Sea temperatures would decrease.
- Greenhouse gases would increase.
- Atmospheric oxygen would increase.
- Sea levels would drastically decrease.

Could you tell me which one is correct?

Greenhouse gases would increase.