Read the passage below and answer the question. The pure contralto sings in the organ loft,

The carpenter dresses his plank, the tongue of his foreplane whistles its wild ascending lisp,

The married and unmarried children ride home to their Thanksgiving dinner,

The pilot seizes the king-pin, he heaves down with a strong arm, (lines 255 – 258)

What does Whitman describe in the passage from "Song of Myself"?

the diversity of the American people
the unity between people and nature
the industrialization of America
the growth of American cities