Phytoplankton are single-celled, photosynthetic organisms living at the surface of the ocean. How do phytoplankton affect the Earth's carbon and oxygen cycles when they perform photosynthesis?

Question

Phytoplankton are single-celled, photosynthetic organisms living at the surface of the ocean. How do phytoplankton affect the Earth's carbon and oxygen cycles when they perform photosynthesis?
 A. 
They add oxygen to and remove carbon dioxide from the atmosphere.
 B. 
They add carbon dioxide to and remove oxygen from the atmosphere.
 C. 
They add both carbon dioxide and oxygen to the atmosphere.
 D. 
They remove both carbon dioxide and oxygen from the atmosphere.

GPT-4o mini · Answer

The correct answer is: **A. They add oxygen to and remove carbon dioxide from the atmosphere.** Phytoplankton perform photosynthesis, which involves using sunlight to convert carbon dioxide and water into glucose and oxygen. Therefore, they play a crucial role in the carbon and oxygen cycles by absorbing carbon dioxide and releasing oxygen into the atmosphere.