Final answer:
The correction of a metabolic acid excess or deficit depends on the normal function of the renal and respiratory systems, which maintain the body's acid-base balance.
Step-by-step explanation:
The body's ability to correct an excess or deficit of a metabolic acid depends on the normal function of the renal and respiratory systems. The renal system adjusts blood pH through the excretion of hydrogen ions and the conservation of bicarbonate, which can take several hours to days. In contrast, the respiratory system can quickly influence blood pH by exhaling carbon dioxide (CO2), thus reducing carbonic acid levels in the blood. Both systems are essential in maintaining the body's acid-base balance and the efficiency of its buffer systems.