The _1__ is a specialized smooth ER only found in muscle cells. It is really important because it has structures called _2___ that bring the action potential, or the electrical
impulse, deep into the cell and releases the ion 3___.

1- sarcoplasmic reticulum

Explanation:

2- electrical current

3-calcium

fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. the core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in.

it means your tired?