Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: Regulation of transcription in prokaryotes typically involves operons. An operon is a region of DNA that consists of one or more genes that encode the proteins needed for a specific function. The operon also includes a promoter and an operator. The operator is a region of the operon where regulatory proteins bind. It is located near the promoter and helps regulate transcription of the operon genes. Answer: operon
[A]: Which region of dna consists of one or more genes that encode the proteins needed for a specific function?

[Q]: Passage: The population is an important unit in ecology as well as other biological sciences. How is a population defined, and what are the strengths and weaknesses of this definition? Are there some species that at certain times or places are not in populations?. Answer: cell division
[A]: During interphase, the cell undergoes normal growth processes while also preparing for what, by accumulating energy and building blocks of dna?

[Q]: Passage: Many teens have emotional ups and downs. This is at least partly due to their changing hormone levels. Answer: hormones
[A]:
Changing levels of what substances partly explain emotional ups and downs in teens?