Which structure is unique to living organisms? A
capsid
B
nucleus
C
cytoplasm
D
nucleic acids

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

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.