Given a scientific question, generate a correct answer to it.

Ex Input:
To undo the tarnish on copper pennies, you can place them in what liquid?

Ex Output:
vinegar

Ex Input:
What are the ionic compounds that produce negative hydroxide ions when dissolved in water?

Ex Output:
bases

Ex Input:
What system carries nerve impulses to internal organs, controlling activities that are not under your control, such as sweating and digesting food?

Ex Output:
autonomic nervous system