This is an anaphoric poem, that is, a poem in which the speaker repeats a word over and over, creating a strong rhythm and drawing attention to the importance of the repeated word. The word is “remember,” which suggests the reader may have forgotten something.

The speaker tells the reader, and therefore all humanity, to “remember” a list of specific ideas that the speaker presents as facts. Presumably, readers have forgotten these facts, which is why the speaker must remind them. A reader can also interpret the repetition of “remember” to mean that the ideas the speaker presents are from an earlier time, either historically or in the life of the reader. She is not presenting new information. She is reminding them of something that has already been established. That is why she uses the word “remember” instead of “imagine,” “discover,” or “believe.”

The cumulative lines of the poem point to a similar theme, which is to remember nature and to treat the elements of the natural world as family. The speaker delineates a large tapestry of the natural world, including the sky, celestial bodies such as the sun, moon, and stars, the earth as a whole, and the plant and animal worlds.