Which components is not found in all circulatory systems?

- a heart that pumps gluid throughout the body

- a cavity within the body that allows organs to be bathed directly in blood

- blood

- a network of blood vessels through which the body travels to all parts of the body

not sure if this what   you'r looking for would be percent composition

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.