After trying to set up words the first time and then seeing what you really meant, I did a different set of words. In the first try I had 3 topics with 15 words each (easy, medium and hard) so I guess I have a lot of material for another go at this section.
I settled on these words and topics:
Easy - Farmer’s Market
- Apple
- Pea
- Lettuce
- Banana
- Orange
Medium - School
- notebook
- teacher
- Principal
- custodian
- classroom
Hard - History Museum
- dinosaur
- plesiosaurus
- herbivores
- cretaceous
- tyrannosaurus