The diaphragm ;) it controls breathing. it's what helps your lungs function.
The function of the cell membrane is to protect the cell from any outer surroundings that could be harmful to it.
The answer is Na + is entering the cell and the K + is leaving, during the depolarization phase of the action potential open Na + channels allow Na + ions to diffuse into the cell. This inward movement of positive charge makes the membrane potential more positive. The depolarization phase is a positive response sequence where open Na + channels cause depolarization which in re-occurrence causes more voltage gated Na+ channels to open.
An invertebrate, because an animal with a vertebrate is an animal with a backbone.
