Biology

The correct answer is: D.Turn atmospheric nitrogen into nitrates.

Free-living nitrogen-fixing bacteria in the soil convert atmospheric nitrogen (N₂) into forms that plants can use, such as ammonium (NH₄⁺), through the process of nitrogen fixation. This is an essential part of the nitrogen cycle, as it provides plants with the nitrogen they need to grow.

Here's why the other options are incorrect:

A.Make carbon dioxide for plants to go through photosynthesis: Plants absorb carbon dioxide from the atmosphere for photosynthesis, but bacteria do not produce it for this p...