question: What do sponges clean?
choices.text: reefs trees aquatic matter dirt retina snails water
choices.label: A B C D E F G H
fact2: Since mussels are filter-feeders, they clean water as they feed.
combinedfact: sponges clean water
formatted_question: What do sponges clean? (A) reefs (B) trees (C) aquatic (D) matter (E) dirt (F) retina (G) snails (H) water