What would most likely happen if airborne pollution blocked the sun's rays so significantly that only 5% of plants survived?

the answer to you question is   jet streams

i think it is dna, i'm not totally sure but i think it might be.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

i thinking chemical change