Final answer:
Severe diarrhea can cause metabolic acidosis due to the loss of bicarbonate ions through the gastrointestinal tract.
Step-by-step explanation:
Severe diarrhea can cause metabolic acidosis due to the loss of bicarbonate ions through the gastrointestinal tract. Bicarbonate ions act as buffers in the body, helping to maintain the pH balance. When there is excessive loss of bicarbonate ions, the pH of the blood decreases, leading to an acidic environment.