What characteristics can you observe in the gills that make them an efficient respiratory organ?

Lots of folding = lots of surface area for diffusion.  

Lots of vascularization.  

Countercurrent exchange system.  

Located off of the throat to help water get rammed down the throat in a single direction, across the gills

answer: after carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed. respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.

explanation:

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.