She means that being a black southerner sucked, but it sucked even worse in the hot summer afternoons, which were hot and humid and uncomfortable and by which time everybody had been working hard all day, than in the mornings, when it was more comfortable and people had just gotten out of bed and weren't completely awake and aware of their lousy situation in life.
In the given story, Marcus had already given up on everything. He felt he lacks motivation, and simply refused to care anymore. And going to junior college doesn't appeal to him at all.
But with the arrival of Shelby, Marcus felt a newfound interest. Observing how much the strange girl reads and is passionate about books that even he has no idea about, Marcus realizes that passion is formed and not something that one is born with. He discovers that one's efforts build passion and with that, comes the rest.
Animals being in captivity is bad for their instincts. In captivity, animals lose their more wild side that's in touch with their original and natural environment. Unless an animal (specifically whales in this case) is injured and cannot be in the wild, they should not be kept in captivity.
