Bob is curious about why his white bread grows mold so quickly. so he asks a question, does some research, creates a hypothesis, and sets up his experiment. he wants to see if his white bread will grow mold in the refrigerator. so he takes one piece of bread and puts it in the refrigerator. he records how much mold grows on the bread each day. he concludes that it takes his bread 10 days to grow mold in the refrigerator. what is bob missing in his experiment?

an independent variable

a dependent variable

a control group

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