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
It's sabroso because sabroso means tasty. ;)
고맙습니다<span>gomabseubnida</span>
hope this helps!!!
Its novel. Although the others may have titles a novel/book has chapter titles. Like Chapter 1, chapter 2, etc
Both changed and started, the two verbs in this sentence, are regular verbs. regular verbs are verbs whose past tense is simply formed by adding -ed to the end of the word. so change is changed, and start is started. hope this helps (-: