The cell theory was developed based upon the research done by many scientists over many years. Which of the following statements is NOT a part of the modern cell theory? A Cells are the basic units of life.
B All organisms are composed of cells.
C All cells are microscopic.
D All cells come from pre-existing cells.

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.