The Native American literature mostly talks about their customs, rituals, values and their knowledge, the stories can be hero tales, migrations legends, accounts of creation or song lyrics, taking this into account the key themes that the American literature uses are the origin of natural phenomena, the sacredness of the natural world and the unending cycle of life.
The preposition in the sentence is under. A preposition is a word meaning where the noun is in the sentence, the noun is tree, the preposition is under.
