just point at things and say "that's a plant". If anyone takes issue, ignore them, bend down to scrutinise your plant and say "hmm, sessile" really thoughtfully, that way they'll know you're the real deal.
I wanted to do some quip about monoecious/bisexual flowers being perfect but then I got stuck reading about the alternation of generations for the first time instead? What the fuck are plants even
My last botany exam had a lot of longform essay questions about successional process and ecological interactions from memory, sorry I don't have a copy available
this was a 3rd year subject on australian vegetation fwiw
Real answer probably some basic stuff about their reproductive systems, some stuff about their cellular makeup, and various pollination mechanisms, root systems, probably different leaf types and waxy vs soft leaves and their evolutionary roots. It's been a looooooong time since my field biology days but if you want I could probably come up with more.
Define symplast, apoplast, cation exchange, quenching (wrt photosynthesis), PAR, and water potential. Other stuff, probs, plant physiology was a while ago for me.