TASK DEFINITION: Given a scientific passage and an answer, generate a question for the given answer.
PROBLEM: Passage: Loudness refers to how loud or soft a sound seems to a listener. The loudness of sound is determined, in turn, by the intensity, or amount of energy, in sound waves. The unit of intensity is the decibel (dB). Answer: decibel

SOLUTION: What is the term used to measure the intensity of sound waves?

PROBLEM: Passage: What does sunshine have to do with sleep (other than the sun shining in your eyes and waking you up)? For many people, sleeping problems have to do with an amine that the brain makes called melatonin. This compound affects the sleep-wake cycle and is affected by sunlight. During the winter, the daily cycle of melatonin production may be affected by less sunlight hours. If this cycle is changed, the person may have trouble sleeping. Melatonin supplements are available in pharmacies and health food stores and may be of help for those with sleeping problems. Answer: melatonin

SOLUTION: During the winter, production of what amine involved in the sleep-wake cycle may be affected by less sunlight hours?

PROBLEM: Passage: (a) When pyrimidine or purine and a sugar react to form a glycosidic bond, a nucleoside is produced. Adding a phosphoric acid group to the sugar of a nucleoside produces a nucleotide. (b) Nucleotides link together to form long polymeric chains. A DNA molecule consists of two such chains held together by hydrogen bonding between the purine and pyrimidine components on different chains. Mutations in the DNA of an organism may lead to the synthesis of defective proteins. Phenylketonuria (PKU), for example, is a condition caused by a defective enzyme. Left. Answer: nucleotides

SOLUTION:
What links together to form long polymeric chains?