Answer:
parasympathetic division; sympathetic division
Fishes gills are engorge in blood , as water is pumped over it as the fish swims, it pulls water thru it's mouth and pushes it over it's gills extracting oxygen and the used water is ejected thru the fish slits opening that cover and protect the gill. the blood is circulated thru the fish body.
Answer:
I am not sure what you are asking but when pH is alkaline it will change the litmus paper to that blue color.
