instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Electromagnetic waves vary in their wavelengths, frequencies, and energy levels. The full range of electromagnetic waves makes up the electromagnetic spectrum. Answer: electromagnetic spectrum
answer:
What do we call the full range of electromagnetic waves?

question:
Passage: - For lenses, the distance from the center of the lens to the focus is . Focal lengths are positive for converging lens and negative for diverging lens. The distance from the center of the lens to the object in question is , where distances to the left of the lens are positive in sign. The distance from the center of the lens to the image is . This number is positive for real images (formed to the right of the lens), and negative for virtual images (formed to the left of the lens). Answer: focal lengths
answer:
What lengths are positive for converging lens and negative for diverging lens?

question:
Passage: Ionic solutes separate into individual ions when they dissolve. Covalent solutes separate into individual molecules. Answer: individual molecules
answer:
Covalent solutes separate into what when dissolved?