The smaller its mass is, the greater its acceleration for a given amount of force.  Will weighs 180 pounds while Nat weights 120 pounds, who would accelerate less after the same force is applied Will or Nat?
Will

Smaller sediments are dropped as the slope becomes less steep.  When looking at a hill, Shane sees that the sand on the steep slopes is finer or thicker?
finer

With a higher the concentration of hydrogen ions, a solution is more acidic and has a lower pH.  Something with less hydrogen ions would have what pH value high or low?
high