Pyramid Game?

Question

So I came across this puzzle similar to the Pyramid Game.

I was wondering if anyone could help me out please? Thanks so much.

2. orange, apple, tomato, grapefruit, cranberry

5. phones, remote controls, dress shirts, short-tempered people, electronics

8. mu, nu, pi, rho, xi

9. boggle, scrabble, balderdash, apples to apples, mad gab

10. Sweeden, Estonia, France, Slovakia, Greece

[hint: if you don't know how to play, it's simply find what these words have in common]

Answer 1

2. Fruits

5. Offices?

8. Greek alphabet

9. Boardgames

10. Foreign/European countries