The answer to your rather difficult question is paper. only certain trees make gum rubber, only certain trees make syrup and none of them make turpentine( an extremely flammable substance. the only thing you can get from almost every tree is paper.
Its simple.. cereal, salad,soup... the teacher wants you to have three common mixtures because the teacher wants to see if you know what things are mixtures in your life. Why i choose CSS/ Cereal,salad,soup because You can drain the milk or take out the cereal.. from cereal, and with a salad you can take out one of the things Ex. Carrot, tomato, chicken, cheese (very hard but you can do it) e.t.c. and soup because you can take out the veggies or meat or noodles.
The model of the atom which was supported by the gold foil experiment was nuclear model.
Scientists wanted to prove plum pudding model, however, their experiments led to interesting results which made them hypothesize the nuclear model of the atom instead.
