^^^^^^^^^^^^^^^^^^^^^^^^^^^ is correct
<span>The answer is C. temperature, light level, species of bacteria. All three variables are considerations regarding the reproduction rate of the bacteria. The other three answer choices can be eliminated easily because they each contain at least one irrelevant variable. In particular, all three contain a variable that makes reference to Jack's personal characteristics. These do not have any impact on the experiment and readily stand out to disqualify the entire answer choice.</span>
