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

Ex Input:
Passage: An addition reaction is a reaction in which an atom or molecule is added to an unsaturated molecule, making a single product . An addition reaction can be thought of as adding a molecule across the double or triple bond of an alkene or alkyne. Addition reactions are useful ways to introduce a new functional group into an organic molecule. Answer: an addition reaction

Ex Output:
What is a reaction in which an atom or molecule is added to an unsaturated molecule, making a single product?

Ex Input:
Passage: Distillation is an effective method to separate mixtures comprised of two or more pure liquids. Distillation is a purification process where the components of a liquid mixture are vaporized and then condensed and isolated. In simple distillation, a mixture is heated and the most volatile component vaporizes at the lowest temperature. The vapor passes through a cooled tube (a condenser), where it condenses back into its liquid state. The condensate that is collected is called distillate. Answer: distillation

Ex Output:
What is a purification process where the components of a liquid mixture are vaporized and then condensed and isolated?

Ex Input:
Passage: Enzymes are biochemical catalysts, which means that they speed up the rate of a specific chemical reaction. A process that might take weeks in the absence of an enzyme can occur in milliseconds if the proper enzyme is present. A generic enzyme-catalyzed reaction could be represented as follows:. Answer: biochemical catalysts

Ex Output:
Enzymes speed up the rate of a specific chemical reaction and is therefore known as what?