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

Ex Input:
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

Ex Output:
The values of which factors are controlled by the experimenter over the course of an experiment?

Ex Input:
Passage: Cycloalkanes are hydrocarbons whose molecules are closed rings rather than straight or branched chains. A cyclic hydrocarbon is a hydrocarbon with a ring of carbon atoms. Answer: carbon atoms

Ex Output:
Cycloalkanes are hydrocarbons whose molecules are closed rings rather than straight or branched chains. a cyclic hydrocarbon is a hydrocarbon with a ring of these?

Ex Input:
Passage: glands in the skin that produce sweat, a salty fluid that helps cool down the body. Answer: sweat

Ex Output:
What do glands in the skin produce to cool down the body?