13. Jane wants to figure out which of two foods is the healthiest for her pet gerbil, Bob, so she decides to conduct an
experiment. She feeds Bob food A for two weeks and then measures how much Bob weighs. Then she switches the food to
gerbil food B for two weeks and measures how much Bob weighs. Throughout the experiment, she gives Bob the same
amount of water each day, and keeps the temperature in the room constant.
What is the independent variable in this experiment?

An independent variable in an experiment is the variable that is changed. Here, the type of food is the only thing that is changed and the amount of water, temperature and other variables were kept constant (same). Thus, the independent variable is the type of food Bob is given.

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