Question

what helps regulate the acid - base balance in the blood?

Explanation:

The respiratory and renal systems play crucial roles. The lungs regulate carbon - dioxide levels (carbonic acid source), and the kidneys can excrete or reabsorb bicarbonate ions. Buffers like bicarbonate - carbonic acid buffer system also act immediately to neutralize acids or bases.

Answer:

The respiratory system, the renal system, and buffer systems.