instruction:
You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You need to come up with a question about the story that requires an understanding of the relationship described in the background paragraph. The generated question should not be answerable without both the background and story. Write a question about the story that requires a relationship in the background paragraph to answer. Check whether your question requires both the background paragraph and the story to answer. If your question can be answered by only one of these, try to rewrite your question so that it requires both. Note that "flipping" a word in the question can give rise to a new question where the answer will be different from the original question. Often, "flipping" a word gives rise to flipping the direction of the relationship, for example, from "increase" to "decrease."
question:
Background Paragraph: Look at the police car in Figure below . The sound waves from its siren travel outward in all directions. Because the car is racing forward (toward the right), the sound waves get bunched up in front of the car and spread out behind it. As the car approaches the person on the right (position B), the sound waves get closer and closer together. In other words, they have a higher frequency. This makes the siren sound higher in pitch. After the car speeds by the person on the left (position A), the sound waves get more and more spread out, so they have a lower frequency. This makes the siren sound lower in pitch. A change in the frequency of sound waves, relative to a stationary listener, when the source of the sound waves is moving is called the Doppler effect . You’ve probably experienced the Doppler effect yourself. The next time a vehicle with a siren races by, listen for the change in pitch. For an online animation of the Doppler effect, go to the URL below. 
Story: A scientist is analyzing two different sounds, one from a deer and one from a zebra, with a device that allows her to see the sound waves of each noise. While looking at the results, she sees that the sound waves for the deer are more closely packed together, but the zebra's sound has very spread out waves.
answer:
Which animal's sound has a higher pitch?


question:
Background Paragraph: A person with a serious brain injury usually suffers permanent brain damage. These brain injuries usually occur when an external mechanical force, such as a violent blow or jolt to the head or body, causes brain dysfunction. An object penetrating the skull, such as a bullet or a shattered piece of the skull, also can cause traumatic brain injury. As a result, the person may have trouble talking or controlling body movements. Symptoms depend on what part of the brain was injured. Serious brain injuries can also cause personality changes and problems with mental abilities such as memory. Medicines, counseling, and other treatments may help people with serious brain injuries recover from, or at least learn to cope with, their disabilities. 
Story: Two friends were involved in a car crash. they both survived, but Mike had a serious brain injury. Vince was OK, he didn't experience any significant injuries.
answer:
Which friend didn't experience problems with mental abilities?


question:
Background Paragraph: The Hawaiian Islands ( Figure above ) are in the central Pacific Ocean. The islands are volcanoes that increase in age from southeast to northwest. The youngest island is the Big Island of Hawaii at the southeast end of the chain. The volcanoes get older through Maui, Kahoolawe, Lanai, Molokai, Oahu, Kauai, and Niihau Islands through the northwest. The Kilauea volcano on Hawaii has been erupting almost continuously since 1983. There are also eruptions at an underwater volcano called Loih. 
Story: Tom and Brad were good friends but lived far away from each other. Tom lived in Hawaii so he visited all the islands and the volcanoes frequently. Brad lived on the East Coast, and he never visited The Hawaiian Islands.
answer:

Which friend lived closer to Lanai island?