I think the answer is D. ( or supported by observations ). Because theories change over time, they both NEED to be proven, they do NOT go off of consensus, but they do NEED to be supported by observations.
I hope this helps.
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.
The symbiosis between a Pistol shrimps and gobies is called Mutual symbiosis. <u>In this process both animals benefit. </u>The shrimp creates and maintains a burrow for both the animals to live in, where as the fish offers protection from predators. When outside of their burrow the fish keeps a keen eye to spot any predator around and sends a warning to the goby through flicking of its tail in cases of a predator approaching.
