Answer:
Whitman had written a long poem and some of the readers might feel bored reading it, so he used this device to give some energy to it. Since anaphora is repetition, it keeps on getting in the mind of the readers thus giving emphasis to the ideas he expresses.
This is the Newton’s third law of motion buddy: If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. Hope it helps :D
Dude, I deifntly do not know
Changes made for the sake of overall effects desired by dramatists.
Using the formula:

Which is, 3.14 x 2^2 (radius is half of diameter)
Which equals 12.56.