In the nitrogen cycle, which step depends exclusively on prokaryotes?
A) runoff into waterways
B) sedimentation into lake bottoms
C) decomposition of detritus
D) fixation in root nodules

Question

Quizplus · Accepted Answer

Fixation in root nodules is the step in the nitrogen cycle that depends exclusively on prokaryotes, specifically on nitrogen-fixing bacteria such as Rhizobium. The other steps in the nitrogen cycle involve a variety of organisms, including plants, animals, fungi, and both aerobic and anaerobic bacteria. Runoff into waterways can involve the movement of fertilizers or other sources of nitrogen pollution, and can lead to harmful algal blooms and other ecological problems. Sedimentation into lake bottoms can occur when excess nutrients such as nitrogen and phosphorus accumulate in water bodies, leading to eutrophication and other issues. Decomposition of detritus can involve a range of organisms that break down dead plant and animal material and release nitrogen back into the ecosystem.

In the Nitrogen Cycle, Which Step Depends Exclusively on Prokaryotes