Final answer:
Yes, H2O can function as a buffer because it can both accept and donate protons. This allows it to resist changes in pH when small amounts of acid or base are added to it.
Step-by-step explanation:
Yes, H2O can function as a buffer. A buffer is a solution that can resist changes in pH when small amounts of acid or base are added to it. H2O can act as a buffer because it can both accept and donate protons (hydronium ions). As a result, it can help to maintain a relatively constant pH in a solution.