Which of these lines from walt whitman's “i hear america singing” describes a unified america?
(i hear america singing, the varied carols i hear,)
those of mechanics, each one singing his as it should be blithe and strong,
(the carpenter singing his as he measures his plank or beam,)
(the mason singing his as he makes ready for work, or leaves off work,)
(the boatman singing what belongs to him in his boat,) the deckhand singing on the steamboat deck, . .

1. seamount a raised footwall block between normal fault creates this 2. syncline break between rocks where a hanging wall rises relative to a footwall 3. hot spring on rolling hills, this a dip between hills 4. volcanic neck created when a block with hanging walls slips down between normal faults 5. caldera underwater volcano that never reaches above sea level 6. horst natural hot water on earth's surface containing many minerals 7. graben underwater volcano whose top is eroded flat by waves 8. crater less than a mile in diameter; looks like a bowl at the top of a volcano 9. guyot magma that filled the central vent that remains after the volcano has eroded 10. reverse fault over 1 mile in diameter; looks like a bowl over a volcano