question: What requires a smooth surface?
choices.text: hornworts skateboards therian mammals amphibians light actinomycetes water air
choices.label: A B C D E F G H
formatted_question: What requires a smooth surface? (A) hornworts (B) skateboards (C) therian mammals (D) amphibians (E) light (F) actinomycetes (G) water (H) air