Treating wastewater can be expensive for starters. A community may not need the water and therefore wouldn't wanna waste their time and money converting it. Some places do not have a storage place for the clean water so they would only be cleaning it to re-pollute it.
The tree may erode or rot in the water or the remains of the tree will sink into the soil
The correct answer to your question is C) Glucose. Hope this helps you out please let me know.
Answer:
"Brachiopoda"
Drosal and ventral valves; Individuals resemble clams; May have no anus
"Bryozoa"
Possesses a chitinous zoecium; Anus opening near mouth; Colonies resemble moss