N 1960, an invasive species of fish was introduced into the stable ecosystem of a river. Since then, the population of a native fish species has declined. This situation is an example of an 1) Ecosystem that has recovered
2) Ecosystems are altered through the activities of humans.
3) Environmental impact caused by physical factors
4) Ecological niche without competition

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.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

airlines i think? or a cruise boat? does this work out for u? ?

not sure what it is