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 are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.

Background Paragraph: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species.
Story: Two students studied animal behavior for the biology class. Ned studied more about predators, while Kim studied more about herbivores.
Question: Which student learned less about deer?
Ned.

Background Paragraph: The example of someone having a positive experience with a drug is easy to see how drug dependence and the law of effect works. The tolerance for a drug goes up as one continues to use it after having a positive experience with a certain amount the first time.[38] It will take more and more to get that same feeling. This is when the controlled substance in an experiment would have to be modified and the experiment would really begin. The law of work for psychologist B. F. Skinner almost half a century later on the principles of operant conditioning, "a learning process by which the effect, or consequence, of a response influences the future rate of production of that response.[39].
Story: The Speed Squad met to discuss their experiences. They all said they always had a great experience using speed and used the same amount each time. They told how many times they used speed. Todd used it 36 times, Jesse used it 40 times, Craig used it 44 times, Alan used it 56 times, Shawn used it 69 times, Clarence used it 78 times, and Sean used it 86 times.
Question: Who has a higher tolerance for speed: Shawn or Sean?
Sean.

Background Paragraph: A comet tailand comaare features visible in comets when they are illuminated by the Sun and may become visible from Earth when a comet passes through the inner Solar System. As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them. Separate tails are formed of dust and gases, becoming visible through different phenomena; the dust reflects sunlight directly and the gases glow from ionisation. Most comets are too faint to be visible without the aid of a telescope, but a few each decade become bright enough to be visible to the naked eye.
Story: Year 2022 would be an interesting year when three comets would get scientists' attention - Comet A, Comet B, and Comet C. Comet A and C are very faint, but Comet B is very bright. Comet A would enter the inner solar system on February 10, 2022 and leave the inner solar system on February 20, 2022. Comet B would enter the inner solar system on February 18, 2022 and leave the inner solar system on February 26, 2022. Comet C would never enter the inner solar system.
Question: Which comet's materials would not steam out of the nucleus, Comet B or Comet C?
Comet C.