A runner uses all available oxygen for respiration. She then notices that her legs are becoming sore. Which of these statements is most representative of respiration? A) She has been running too long.
B) Her body is producing lactic acid as a result of doing anaerobic respiration.
c) Her body is producing lactic acid because she is breathing too hard.
D) Her body is producing lactic acid as a result of doing aerobic respiration.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.