<em>Anything</em> that's dropped through air is somewhat affected by air resistance. But, out of that list, the leaf and the balloon are the items that will be affected by air resistance enough so that you can plainly see it.
If you spend some time thinking about it, you can kind of understand why airplane wings and boat propellers are shaped more like leafs and balloons than like bricks and rocks.
It must be a mixture, because the ingredients can be separated. You can precipitate sugar from water, there's no chemical reaction involved. I actually made lemonade pops once and the lemon juice and sugar comes out of solution as the water freezes.
C^2=a^2+b^2
c^2=45^2+45^2
c^2=4050
c=63.64
c=64
The answer is D.
