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

[EX Q]: Passage: Are you on the basketball team? Are you a cheerleader? Do you play an instrument in the band? Your niche would be your role or place in the school. Organisms also each have their own niche in the ecosystem. Is an organism a producer or a consumer? How does the organism interact with other organisms? Is the organism involved in any symbiotic relationships?. Answer: niche
[EX A]: An organism's unique role in the ecosystem is called its what?

[EX Q]: Passage: Dissolved mineral salts wash into the ocean. As ocean water evaporates, it leaves the salts behind. This makes the water saltier. Ocean water is about 3.5 percent salts. The main salt is sodium chloride. Answer: salts
[EX A]: Concentration of what, the substance left behind when ocean water evaporates, is about 3.5 percent?

[EX Q]: Passage: In prokaryotes, a combination of activators and repressors determines whether a gene is transcribed. As you know, prokaryotic organisms are fairly simple organisms with much less DNA. Prokaryotic genes are arranged in operons , a region of DNA with a promoter, an operator , and one or more genes that encode proteins needed to perform a certain task. To maintain homeostasis (and survive), the organism must quickly adapt changing environmental conditions. The regulation of transcription plays a key role in this process. Answer: homeostasis
[EX A]:
In order to survive and maintain what state, an organism must quickly adapt to changing environmental conditions?