Question

to investigate bacterial metabolism, a researcher divided a population (culture) of staphylococcus capitis bacteria into two sets of culture tubes containing glucose. the researcher added a chemical to one set of tubes and measured the ph of the cultures at 5 - minute intervals as the bacteria metabolized the glucose into lactic acid. the data are shown in table 1.
table 1 average change in ph in control and treatment groups over a 40 - minute period
which of the following was the dependent variable in the researchers experiment?
a time
b ph
c glucose concentration
d lactic acid concentration

Explanation:

The dependent variable is the outcome being measured. Here, the experiment measures pH changes over time in control and treatment groups, so pH is the dependent variable. Time is independent, while glucose and lactic acid concentrations are not the measured outcome in this context.

Answer:

B. pH