The pronouns shift from “his” to “she”.
The central idea is what the main thing. For this, I think the central idea is simply Cactuses.
I'm not sure what another supporting detail can be, but if there's a back side, or another page about cactuses, I can sure help! But if that's the only side, ask your parents. xD
The answer is A i briliev:)
The answer is C because they all distort the way the earth looks.