Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Ex Input:
Mucous does the esophagus produce for lubrication.

Ex Output:
What does the esophagus produce for lubrication?

Ex Input:
According to the english system measurement, 4 cups much is equal to 2 pints, 1 quart, and of a gallon.

Ex Output:
According to the english system measurement, how much is equal to 2 pints, 1 quart, and of a gallon?

Ex Input:
Growth factors and certain plant and animal hormones serve as molecular messengers that initiate pathways of cell division.

Ex Output:
Growth factors and certain plant and animal hormones serve as molecular messengers that initiate pathways of what?