Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: A variable is a factor that can change over the course of an experiment. Independent variables are factors whose values are controlled by the experimenter to determine its relationship to an observed phenomenon (the dependent variable). Dependent variables change in response to the independent variable. Answer: independent variables
[A]: The values of which factors are controlled by the experimenter over the course of an experiment?

[Q]: Passage: Compared to Earth, the solar system is a big place. But galaxies are bigger - a lot bigger. A galaxy is a very large group of stars held together by gravity. How enormous a galaxy is and how many stars it contains are impossible for us to really understand. A galaxy contains up to a few billion stars! Our solar system is in the Milky Way Galaxy. It is so large that if our solar system were the size of your fist, the galaxy's disk would be wider than the entire United States! There are several different types of galaxies, and there are billions of galaxies in the universe. Answer: milky way
[A]: What galaxy is our solar system a part of?

[Q]: Passage: Cleaning groundwater in an aquifer requires bioremediation or chemical remediation. Bioremediation uses microorganisms to consume a pollutant. Chemical remediation destroys the contaminant. Answer: bioremediation
[A]:
What do you call a process that uses microorganisms to consume a pollutant?