Homeostasis can be disrupted by many factors. External stimuli that can disrupt homeostasis include & outside temperature. Internal stimuli include & water concentration.
A) pathogens, blood pressure
B) blood pressure, pathogens
C) insulin production in body, toxins
D) toxins, insulin production in body

Pathogens and blood pressure

energy and particles

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.