Question

5 multiple choice 1 point the first essential step in changing atmospheric nitrogen into more usable ammonia (nh₃) is called biogeochemical cycling ammonification nitrification denitrification nitrogen fixation clear my selection

Explanation:

To solve this, we analyze each option:

• Biogeochemical cycling: Involves nutrient cycles (like N, C) but not the specific step of converting atmospheric N to ammonia.
• Ammonification: Converts organic N to ammonia, but starts from organic matter, not atmospheric N.
• Nitrification: Converts ammonia to nitrites/nitrates, not the reverse.
• Denitrification: Converts nitrates back to atmospheric N, opposite of what's needed.
• Nitrogen fixation: The process of converting atmospheric nitrogen ($N_2$) into ammonia ($NH_3$) or other usable nitrogen compounds, which matches the description.

Answer:

E. nitrogen fixation