1. C. backbreaking work from dawn to dusk
At that time, enslaved people were not considered as humans by the slave owners. In modern day's equivalent, they are treated closer to a cattle than to humans.
They are forced to work form dawn to dusk without any rewards. But they would be severely punished or killed if their works does not fulfill the expectation of the owners.
2. D. Liberia
At that time, the american colonization society was established to help people of color to escape slavery from america. They provided ships or other medium transportation to African continent so the freed slaves were not caught by the southerners who conducted a hunt to kill them,. Liberia was considered to be one of their main destination.
3. C. slaves and slaveholders depended on one another.
In the southener's point of view, they depended on one another because they feel that they somehow help the slaves' life and educate them. While in fact the slaves were only used for the slave owner's economic benefit and forced to works everyday. without any pay.