The line that shows how the author feels connected and related to all of humanity is: "For every atom belonging to me as good belongs to you."
We can arrive at this answer because:
The poem reinforces the idea that all elements of the planet are connected and must act in line with each other.
This question is about the poem "Song of Myself" and you can find more information about this poem here:
https://brainly.com/question/2799277