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

[EX Q]: Passage: To harness water power, a stream must be dammed. Narrow valleys are the best for dams. While sitting in the reservoir behind the dam, the water has potential energy. Water is allowed to flow downhill into a large turbine. While flowing downhill, the water has kinetic energy. Kinetic energy makes the turbine spin. The turbine is connected to a generator, which makes electricity. Answer: kinetic energy
[EX A]: Water is allowed to flow downhill into a large turbine to harness power. what helps the turbine spin?

[EX Q]: Passage: Viruses , like the one depicted in Figure below , are tiny particles that may cause disease. Human diseases caused by viruses include the common cold and flu. Do you think viruses are prokaryotes or eukaryotes? The answer may surprise you. Viruses are not cells at all, so they are neither prokaryotes nor eukaryotes. Answer: viruses
[EX A]: The common cold and flu are examples of human diseases caused by what tiny particles?

[EX Q]: Passage: When light rays diverge in front of a mirror, a virtual image is formed. A virtual image is formed by your brain tracing diverging rays backwards and is kind of a trick, like the person you see "behind" a mirror's surface when you brush your teeth (there's obviously no real light focused behind a mirror!). Since virtual images aren't actually "anywhere," you can't place photographic film anywhere to capture them. Answer: virtual
[EX A]:
What type of image is formed when light rays diverge in front of a mirror?