question: what play significant roles as producers in aquatic ecosystems?
choices.text: animals in Class Aves hornworts trees liverworts sunshine carbon polymorphs hydrogen and oxygen nonvascular plants
choices.label: A B C D E F G H
formatted_question: what play significant roles as producers in aquatic ecosystems? (A) animals in Class Aves (B) hornworts (C) trees (D) liverworts (E) sunshine (F) carbon polymorphs (G) hydrogen and oxygen (H) nonvascular plants