The correct answer is:
The natural aspects of life.
Explanation:
Walt Whitman is one of the greatest American poets, in his poem Song of Myself, as it name says he celebrates himself and how nature created all things in this world. He starts by celebrating himself, and encourages others to celebrate themselves as well. During the poem he celebrates how everything belongs to the right time in space, he also celebrates vegetation and seasons changing, this poem is about celebrating natural aspects of life and being alive.