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: Apex predators affect prey species' population dynamics and populations of other predators, both in aquatic and in terrestrial ecosystems. Non-native predatory fish, for instance, have sometimes devastated formerly dominant predators. A lake manipulation study found that when the non-native smallmouth bass was removed, lake trout, the suppressed native apex predator, diversified its prey selection and increased its trophic level. As a terrestrial example, the badger, an apex predator, predates on and also competes with the hedgehog, a mesopredator, for food such as insects, small mammals, reptiles, amphibians and ground-nesting bird's eggs. Removal of badgers (in a trial investigating bovine tuberculosis) caused hedgehog densities to more than double. Predators that exert a top-down control on organisms in their community are often considered keystone species. Humans are not considered apex predators because their diets are typically diverse, although human trophic levels increase with consumption of meat. 
Story: Rob is a biologist who is interested in native species conservation. To that end, he conducted two studies, case A and case B. In case A, a non native apex predator C was introduced in formerly apex predator D's habitat. In case B, same non native apex predator C was removed from formerly apex predator D's habitat. He now needs to analyze the results of these studies. 
Question: Would predator D's trophic level increase or decrease in case B than in case A?
Example Output: increase.

Example Input: Background Paragraph: About 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. 
Story: White mountains are often visited by tourists because of the many beautiful caves, stalactites, stalagmites and karst phenomena. Dome mountains are interesting to tourists because they are very massive, of volcanic origin and excellent for climbing. 
Question: Which mountain is made of less soluble rock?
Example Output: Dome.

Example Input: Background Paragraph: Plants called epiphytes grow on other plants. They obtain moisture from the air and make food by photosynthesis. Most epiphytes are ferns or orchids that live in tropical or temperate rainforests (see Figure below ). Host trees provide support, allowing epiphyte plants to obtain air and sunlight high above the forest floor. Being elevated above the ground lets epiphytes get out of the shadows on the forest floor so they can get enough sunlight for photosynthesis. Being elevated may also reduce the risk of being eaten by herbivores and increase the chance of pollination by wind. 
Story: While hiking Bob likes to collect plant specimens. Yesterday, he was hiking along a creek, and was specifically looking for epiphytes. Eventually, he found one, and tagged the specimen as specimen A. To compare specimen A with another plant he collected another plant specimen that was not an epiphyte. He tagged that specimen as specimen B. 
Question: Which specimen would not grow on other plants, specimen A or specimen B?
Example Output:
specimen B.