Which ions play a significant role in maintaining acid-base balance in the body?

The correct response reflects the crucial involvement of anions in maintaining the body's acid-base balance. Among the various ions present in the body, anions such as bicarbonate (HCO3-), chloride (Cl-), and phosphate (PO4^3-) are vital in buffering acids and bases, thereby helping to stabilize the pH level of bodily fluids.

Bicarbonate, in particular, acts as a key component of the bicarbonate buffer system, which is one of the primary mechanisms through which the body regulates acidity. This buffer system can quickly neutralize excess acids or bases, promoting homeostasis.

While cations such as sodium (Na+) and potassium (K+) are essential for various physiological functions, including nerve impulses and muscle contraction, their role in direct acid-base regulation is not as significant as that of anions. Electrons are elementary particles that are not ions and do not participate directly in acid-base balance. Proteins can act as buffers through their amino acid side chains, but they do not function as ions in the same manner as anions or cations. Therefore, anions are specifically recognized for their primary role in managing acid-base equilibrium in the body.