two science questions?

Question

ok here they are:
1. How are atoms different from molecules?
2. If you mix salt, sand, and sugar with water in a small jar, will the result be a suspension, a solution, or both?

ok for #1 i have no idea and for #2 i think it's both because a suspension is a solution but a solution is not a suspension and because it's spread out evenly by a liquid
but i'm not sure if the the particles will sink

please and thank you ^ ^

oops sorry one more question:
3. In what way are cell membranes selectively permeable?

ok for #3 i think it's because it allows somethings to move in and out of the cell (but i think i'm wrong)

Answer 1

#1 - Molecules are made from atoms.
#2 - Both, but only for a short while. The salt and sugar will dissolve in the water and stay that way in solution. The sand will be in suspension for a short time after you shake it up until it settles by gravity.
#3 - Yes