It's the sodium ion.
When a neural impulse is fired in both neurons, it is always cause by an excited electron in one neuron moving to the other neuron to destabilize the balance of ions trying to keep them at equilibrium. This action either depolarizes or hyper-polarizes the membrane. If it does, then sodium ions--the key deficient ones--can flow into that region of low charge and maintain that state of low charge, keeping the cell membrane stable.
Answer:
So this is just a guess but i think its D but like I said its a guess.
This is called a chemical bond.
Explanation:
Well, one could use a magnet to see if it's ferrous. One could melt it to check which type it is, use a metal detector, or just use their senses: If it dings or clinks like metal, and feels like it’s texture. If it polishes with metal polish, is reflective, can be shaped or shape when heated… It usually is a metal. If it rusts, or oxidizes, it is or contains metal. If it “smells" like metal, most likely, it is metal. Finally, if it walks like metal, and quacks like metal, most likely we have a metal
im not to sure, but i think its 21.95
hope this helps! :)