What environmental evidence is the investigation looking for?

• A. Evidence of New Wildlife Species Colonization
• B. Evidence of Archaeological Artifacts
• C. Evidence of Erosion, Siltation, or Obstructions in Nearby Tributaries and Waterways
• D. Evidence of Soil Nutrient Depletion Affecting Crops

Answer: (C)

The main idea here is identifying visible signs of how land disturbances show up in nearby water systems. The investigation looks for signs that land-use or erosion is affecting streams and rivers, specifically sediment-related changes and blockages.

Evidence of erosion and siltation in nearby tributaries and waterways points to soil being washed into waterways, which increases turbidity, harms aquatic habitats, and reflects ongoing land disturbance. Obstructions in waterways—like debris or man-made barriers—alter flow, trap sediment, and disrupt ecosystems. Together, these indicators directly reveal how the watershed is being impacted and how water quality and habitat are affected.

Other possibilities miss the direct link to waterway health: new wildlife species colonization relates to biodiversity changes rather than sediment or flow issues; archaeological artifacts aren’t environmental indicators; and soil nutrient depletion concerns land fertility rather than sediment and obstruction problems in streams.