[weiming]

I agree with BobK:

And so we see the article can be used to emphasise that two things are separate--I fear the storm, the thunder and the lightning.

The boys and girls lumps them together as one group. The boys and the girls marks them as distinct, separate groups.

You also had the repeated preposition.

"There may be clues in the questions and answers."/ "There may be clues in the questions and in the answers (as well)."

The second "in" is slightly redundant, but there's nothing wrong with it grammatically that I can see.