Final answer:
Saliva is most effective in minimizing an acid challenge by its buffering capacity.
Step-by-step explanation:
Saliva is most effective in minimizing an acid challenge by its buffering capacity. Bicarbonate and phosphate ions in saliva function as chemical buffers, maintaining saliva at a pH between 6.35 and 6.85. These buffers help to neutralize the acid and maintain a favorable environment for the enzymes in saliva to function properly.