Why does the x axis of a dose-response curve use log units?

Applying logarithm to the x axis of the dose response curve is a math trick that will linearize the middle zone of the curve and will allow you to visualize better  the  EC50 of the drug. Also the numbers on the x axis are easier to write since they are larger when you apply the logarithm to the concentrations.

answer; /// i believe the correct answer is (reactants);