question: Ancestors of hagfish are thought to have been the earliest creatures with what?
choices.text: pigment bones keratin life shells size wings arms
choices.label: A B C D E F G H
fact2: Bone is found only in vertebrates .
combinedfact: Ancestors of hagfish are thought to have been the earliest creatures with bones
formatted_question: Ancestors of hagfish are thought to have been the earliest creatures with what? (A) pigment (B) bones (C) keratin (D) life (E) shells (F) size (G) wings (H) arms