What is the best way to classify two different organisms that have similar appearance and are found in the same environment?

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.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex