Which of the following is an example of a nonporous surface?

A nonporous surface is characterized by not allowing liquids or gases to penetrate through it, which makes it an ideal medium for collecting certain types of evidence, such as fingerprints or trace materials. Glass is a prime example of a nonporous surface because it does not absorb moisture or other substances, making it easy to recover and analyze evidence from its surface without the interference of absorption.

In comparison, paper and cloth are both porous materials that can absorb substances, making them unsuitable for certain types of evidence collection, as they could compromise the integrity of the evidence. Unfinished wood, despite being solid, has a porous nature due to its texture and can absorb liquids, which also classifies it as a porous surface. Therefore, glass stands out as the only nonporous surface in this context, facilitating clear evidence collection.