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.

Example Input: Background Paragraph: Centripetal force is, simply, the force that causes centripetal acceleration. Objects that move in uniform circular motion all have an acceleration toward the center of the circle and therefore, they must also suffer a force toward the center of the circle. That force is the centripetal force. For orbiting satellites, such as the moon orbiting the earth or the earth orbiting the sun, the centripetal force is produced by gravity. When an Olympic hammer thrower whirls a massive ball on a chain, the centripetal force is created by the athlete and transmitted by the chain.
Story: Adam wants to show his little brother a trick. He gets a bucket of water and says to him "I bet i can turn this bucket upside down and no water will fall out". His brother doesn't believe him of course. So Adam takes the bucket by the handle and quickly starts spinning it in a circle.
Question: Given Adam stops swinging the bucket, will its centripetal acceleration increase or decrease?
Example Output: decrease.

Example Input: 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?
Example Output: Ned.

Example Input: Background Paragraph: Collision theory tells us that molecules need to collide in order for a reaction to take place. All else being equal, anything that increases the frequency of collisions would also increase the rate of reaction. One way to do this is to increase the concentrations of one or more of the reactants. Using a real world example, a busy freeway will experience much more frequent car collisions than a fairly empty neighborhood street. Similarly, forcing more randomly moving molecules into the same amount of space will cause an increased number of collisions over a given length of time, providing the reactants with more opportunities to transform into products.
Story: Rob wanted to learn more about collision theory. For that, he conducted two tests, test A and test B. In test A he used lower concentration of reactants. In test B he used higher concentration of reactants. Now, he needs to know about the science behind these tests.
Question: In which test reactants would get more opportunies to trasform into products, test A or test B?
Example Output:
test B.