question: pupa:butterfly
choices.label: A B C D
choices.text: ugly duckling:white swan embryo:baby seed:flower tadpole:frog
explanation: the life of a "butterfly" goes through four developmental stages: egg, larva, "pupa" and adult, which is called complete metamorphosis. "chrysalis" belongs to a stage of metamorphosis of "butterfly". both "ugly duckling" and "white swan" belong to animals, "ugly duckling" and "white swan" are two different animals, and "ugly duckling" is not a stage of the growth of "white swan". the "embryo" belongs to one of the entire developmental stages of the "baby", and the life of the "baby" is not a metamorphosis. "seed" is one of the growth stages of a "flower", but "seed" is not metamorphosis. the development process of a "frog" generally goes through four stages: fertilized egg, "tadpole", young frog, and adult frog. "tadpole" belongs to a stage of "frog" metamorphosis.
relation: ugly duckling white swan R2.4