Answer;
-Protein ions
A resting axon's fluid interior has a mostly negative charge thanks to the presence of large protein ions.
Explanation;
-Intracellular and extracellular fluid of neurons contain various kinds of charged ions. These include sodium (Na+), potassium (K+), and chloride (Cl-). Additionally, these fluids contain many negatively charged protein molecules called anions (A-).
-The movement of such ions across neural membranes creates electrical activity. As ions move in and out of the cell, they bring their respective charges (either positive or negative) with them, thus influencing the voltage of cellular membranes.
-The protein molecules are large negatively charged proteins (anions) that are manufactured inside cells. They always remain inside the cell, as there are not membrane channels through which they can leave.Their charge contributes to the negative charge on the intracellular side of the membrane.
