Teacher: Given a scientific passage and an answer, generate a question for the given answer.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Passage: A frameshift mutation is a deletion or insertion of one or more nucleotides that changes the reading frame of the base sequence. Deletions remove nucleotides, and insertions add nucleotides. Consider the following sequence of bases in RNA:. Answer: nucleotides.
Solution: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Reason: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

Now, solve this instance: Passage: Paint keeps oxygen and water from coming into direct contact with the metal, which prevents corrosion. Paint is more necessary because salt is an electrolyte that increases the conductivity of water and facilitates the flow of electric current between anodic and cathodic sites. Answer: corrosion
Student:
Paint keeps oxygen and water from coming into direct contact with the metal, which prevents what?