Biology CLEP Prep Practice Exam

What process produces nitrogen compounds in the atmosphere?

1. Nitrogen fixation

2. Photosynthesis

3. Respiration

4. Fermentation

The correct answer is: Nitrogen fixation

Nitrogen fixation is the process that converts nitrogen gas from the atmosphere into other compounds that can be used by plants and animals. It is the only process out of the given options that produces nitrogen compounds in the atmosphere. Photosynthesis, respiration, and fermentation all play important roles in the nitrogen cycle, but they do not produce nitrogen compounds in the atmosphere. Photosynthesis produces oxygen and glucose, respiration produces energy and carbon dioxide, and fermentation produces energy and various byproducts such as ethanol. Therefore, they are all incorrect options for this question.