What is bioassessment in aquatic ecosystems, and how are macroinvertebrate indices used to evaluate water quality?

• A. Bioassessment is determined solely from chemical concentrations in water.
• B. Macroinvertebrate indices like EPT richness measure weather patterns.
• C. Assessment based on living organisms; macroinvertebrate indices (e.g., EPT richness, chironomids) correlate with toxicity and water quality; used to classify streams.
• D. Macroinvertebrate indices measure dissolved oxygen only.

Answer: (C)