This is a hard one....
I'd say, future tense... Or probably present. Sorry if I got it wrong for you!
But still, I hope this helps you. :)
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
