Digestion and other biological processes are controlled by enzymes. Amylase is an enzyme which breaks starch into glucose.
A student investigated the effect of different pH on the rate of amylase activity. They followed the method below.
a. Known volumes and concentrations of starch and amylase solutions were placed in water baths at 37oC.
b. Buffer solutions of pH 5-9 were placed in different starch solutions.
c. Starch solutions and amylase solutions were mixed.
d. Every 10 seconds they tested the mixture for the presence of starch and the results were recorded.
Identify the independent variable in this experiment.