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

Ex Input:
Passage: Chemical cells are found in batteries. They produce voltage by means of chemical reactions. Chemical cells have two electrodes, which are strips of different materials, such as zinc and carbon. The electrodes are suspended in an electrolyte. This is a substance that contains free ions, which can carry electric current. The electrolyte may be either a paste, in which case the cell is called a dry cell, or a liquid, in which case the cell is called a wet cell. Flashlight batteries contain dry cells. Car batteries contain wet cells. Answer: chemical

Ex Output:
Batteries produce voltage through what type of reaction?

Ex Input:
Passage: Opposite charges attract, and like charges repel. Answer: attract

Ex Output:
What do opposite charges do to one another?

Ex Input:
Passage: Bonds break and reform during chemical reactions. Reactants and products contain the same atoms, but they are rearranged during the reaction, so reactants and products are different substances. Answer: reactants

Ex Output:
In a chemical reaction, what, in general, comes together in order to form a product?