Which of the following is one way that the circulatory system maintain body temperature? carrying heat around the body controlling the flow of blood to the skin carrying nutrients and energy to cells speeding up the blood flow to generate heat (only answer if you took the test! i keep finding different answers and i don't know which one is correct)

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.