What best defines direct evidence in the context of pollution investigation?

Direct evidence refers to information or data that provides an immediate and clear link to the event or situation being investigated. In the context of pollution investigation, first-hand observation of a spill is considered direct evidence because it comes from someone who has personally seen the event occur. This type of evidence is powerful as it offers immediate insights into the circumstances surrounding the spill, including the time, location, and possibly the dynamics of the event.

When investigators rely on direct evidence, they can form stronger conclusions about the source and impact of pollution, as opposed to relying on second-hand reports or interpretations. Other options, such as expert analysis, complaints, or maintenance logs, can provide valuable context or support, but they are not as immediate or unequivocal as witnessing the event itself. Having direct observations allows responders to build a more robust case against responsible parties and ensures that any reactions or remediations are based on verifiable facts.