It is supposed to flow through so heterotrophs(like humans etc) can gain energy from plants(autotrophs) which other animals gain energy from them eating each other which follows the food chain. Which keeps the food chain and life in order, by giving energy for work and life to sustain.
The answer would be C
The illness doesn't have to be life-threatening to the point where they must go to the hospital, but it could still be a health risk.
Drug use leads to criminal activity
