Well, both are foods from plants.
Both are foods
Big circle, food
two smaller, non- overlapping areas inside. One is animal, the other is plant.
Inside the plant one you have vegetable and fruit areas. (inside the animal one you might have land animal and sea animal foods)
Now unfortunately I am afraid I do not know of any foods that are both vegetable and fruit. If I could think of one the vegetable and fruit circles would overlap and inside the overlap ("intersection of fruit and vegetable sets") you would have that "banana-spinach" or whatever.)
Since a Venn diagram has two (or more) overlapping circles, he should put the fruits in one circle and the vegetables in the other. In the part where the circles overlap, he can put in the fruits and vegetables that have some similarities. One strategy would be to put tomatoes in this part because although we consider tomatoes as they are vegetables, technically they are fruits. Another strategy might be to put fruits and vegetables of the same color in the overlapping part -- for instance -- only yellow fruits and vegetables such as bananas, pineapple, squash and yellow beans.
Has his teacher given the class any guidelines for the survey question? Can it be as simple as just asking each classmate to name three things s/he likes to do on weekends? Of can it be a checklist that might include, watching cartoons, playing outdoors, playing video games?
Ah, good, thank you for coming up with a vegetable-fruit Ms. Sue!
You're welcome, Damon.