Question

Jack is planning an experiment to see how temperature can affect the reproduction rate of a certain species of bacteria. Jack is listing some of the variables that could affect the outcome of the experiment. Which of the following variables should be included on his list?
A.time of year, clothes Jack wears, Petri dish mass
B. food Jack eats, day of week, number of pages in log book
C. temperature, light level, species of bacteria
D. time of day, color of walls in lab, Jack's height

Answer 1

Answer:

temperature, light level, species of bacteria

Explanation:

Answer 2

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.