Im not sure but if you think of it, the one that you didn't put any salt is a independent variable because it doesn't really rely on anything it doesn't have salt. The Dependent variable would be the 2nd and the 3rd cup because it doesn't have much salt but the 4th cup has lots of salt so its basically controlled. Hope it helps !
<span>photosynthesis in algae cells </span>
Atoms are so small and its easier to controll it that way. hope that helps
air pressure is usually exerted counterclockwise
