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

Ex Input:
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

Ex Output:
Which region of dna consists of one or more genes that encode the proteins needed for a specific function?

Ex Input:
Passage: Carbohydrates include sugars, starches, and fiber. Sugars and starches are used by the body for energy. One gram of sugar or starch provides 4 Calories of energy. Fiber doesn't provide energy, but it is needed for other uses. At age 13 years, you need about 130 grams of carbohydrates a day. Figure below shows good food sources of each type. Answer: 4

Ex Output:
How many calories of energy does one gram of sugar or starch provide?

Ex Input:
Passage: Elements involved in nuclear reactions are radioactive. How do you think radioactive elements differ from other elements?. Answer: radioactive

Ex Output:
Elements involved in nuclear reactions are what?