Question

you expose the bacterium staphylococcus aureus to low levels of the antibiotic methicillin. the surviving bacteria are then exposed to higher concentrations of methicillin and the process repeated until a strain of methicillin - resistant s. aureus (mrsa) is remaining. to test your hypothesis, you perform an experiment by spreading the original strain of s. aureus and the mrsa strain onto agar plates containing methicillin, and only the mrsa survives. which of the following are dependent variables in this experiment? the strain of s. aureus the dose of methicillin the agar plates survival in the presence of methicillin the time of bacterial growth

Explanation:

A dependent variable is the outcome measured in an experiment, which changes in response to the independent variable. In this experiment, the independent variable is the strain of S. aureus (original vs MRSA), and the measured outcome is whether the bacteria survive in the presence of methicillin. The other options are either independent variables (strain, methicillin dose), experimental materials (agar plates), or an unmeasured control factor (growth time).

Answer:

survival in the presence of methicillin