Plecoptera is part of which index?

Plecoptera is part of which index?

• A. MNO Index
• B. PQR Index
• C. STU Index
• D. ETP Index

Answer: (D)

The idea being tested is using a standard aquatic bioassessment index that combines three orders of aquatic insects: Ephemeroptera, Plecoptera, and Trichoptera. This EPT (or ETP) index is used because these groups are sensitive to pollution and good oxygen conditions, so their presence and relative abundance reflect stream health. Plecoptera, the stoneflies, are a key component of this index, and their occurrence boosts the overall EPT score, signaling cleaner, well-oxygenated water. Other named indices aren’t the standard trio used for this kind of assessment, so they don’t apply here.

The idea being tested is using a standard aquatic bioassessment index that combines three orders of aquatic insects: Ephemeroptera, Plecoptera, and Trichoptera. This EPT (or ETP) index is used because these groups are sensitive to pollution and good oxygen conditions, so their presence and relative abundance reflect stream health. Plecoptera, the stoneflies, are a key component of this index, and their occurrence boosts the overall EPT score, signaling cleaner, well-oxygenated water. Other named indices aren’t the standard trio used for this kind of assessment, so they don’t apply here.