Given a statement, generate a question such that the answer is contained in that statement.

Let me give you an example: Neurons deliver electrical impulses to other cells
The answer to this example can be: What do neurons deliver to other cells?
Here is why: The question generated is valid regarding the information in the statement.

OK. solve this:
Cooling things is a way to keep perishable foods.
Answer:
What is a way to keep perishable foods?