He will most likely find that the sand has sunken to the bottom because the molecules in sand are to powerful to break apart and disslove.
I believe C is the balanced equation.
Answer:
The one that gives you more energy!
Explanation:
<span>Concentration of a chemical in a solution refers to how many of the chemical's molecules are sitting in a small volume of the solution. Concentration could be measured in molecules per liter, although molecules are so small compared to a liter that we usually use different units (just like we wouldn't want to measure the distance between the earth and the sun in inches). A gradient is a measurement of how much something changes as you move from one region to another. So a concentration gradient is a measurement of how the concentration of something changes from one place to another.
If this doesn't help here's a Khan Academy video </span><span>https://www.khanacademy.org/...and.../concentration-gradients</span>
