TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: Wavelength is one way of measuring the size of waves. It is the distance between two corresponding points on adjacent waves, and it is usually measured in meters. How it is measured is a little different for transverse and longitudinal waves. Answer: waves

SOLUTION: What do wavelengths measure the size of?

PROBLEM: Passage: Acidity is measured on a pH scale. Rain that is 5.0 or less on that scale is considered acid rain. Answer: ph scale

SOLUTION: Acidity is measured on what kind of scale?

PROBLEM: Passage: Biofuels are useful because they are liquid. Biofuels can go into a gas tank unlike many other types of alternative energy. Answer: liquid

SOLUTION:
What form do biofuels take that makes them very useful?