There is an exercise in Gateway B1 Student's book, page 13, where you need to choose the correct article.
The answer key for this sentence:
The results show that ∅ / the teenagers who eat with their families five or six times a week usually get top marks at school.
says that we can't have 'the' article here, but why?
In my opinion, we're not talking about all of the teenagers in the world (not talking about teenagers in general), we're just talking about a particular group of teenagers who usually have dinner with their families. Shouldn't we use 'the' article instead?
There is another sentence in the previous exercise: I don't like (the) food at school. We're not talking about food in general, right? And the answer key agrees with us saying 'the' is the only possible option here. Where is ∅/the logic?