Question

level 4
which shows the correct pathway for nitrification?
a. ammonium → nitrite → nitrate
b. ammonia → nitrite → nitrate
c. ammonia → nitrate → nitrite
d. both a and b

Explanation:

Nitrification is a two - step process in the nitrogen cycle. First, ammonia or ammonium is oxidized to nitrite by ammonia - oxidizing bacteria. Then, nitrite is oxidized to nitrate by nitrite - oxidizing bacteria. Both ammonium and ammonia can be starting substances for nitrification.

Answer:

D. Both A and B