Question

in the nitrogen cycle illustrated above, nitrification occurs in which of the following steps?
a step 1
b step 2

Explanation:

Nitrification is the process of converting ammonium ($NH_4^+$) to nitrite ($NO_2^-$) and then to nitrate ($NO_3^-$). In the nitrogen cycle diagram, Step 3 shows the conversion from Ammonium ($NH_4^+$) to Nitrite ($NO_2^-$) and Nitrate ($NO_3^-$), which matches the nitrification process. Step 1 is nitrogen fixation (converting $N_2$ to organic nitrogen), Step 2 is ammonification (organic nitrogen to ammonium), and Step 4 is denitrification (nitrate/nitrite to $N_2$). So nitrification occurs in Step 3 (assuming the options include Step 3; since the visible options start with A: Step 1, and likely other options like Step 3 exist, but based on the cycle, Step 3 is nitrification).

Answer:

(Assuming the correct option is the one for Step 3; if options are A: Step 1, B: Step 2, C: Step 3, D: Step 4, then) C. Step 3