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.

[Q]: Background Paragraph: Fish mortality is a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock through death. The mortality can be divided into two types:

Natural mortality: the removal of fish from the stock due to causes not associated with fishing. Such causes can include disease, competition, cannibalism, old age, predation, pollution or any other natural factor that causes the death of fish. In fisheries models natural mortality is denoted by (M).[1]
Fishing mortality: the removal of fish from the stock due to fishing activities using any fishing gear.[1] It is denoted by (F) in fisheries models. 
Story: Bob works as a scientist for a large fishing company in Norway. Norway's government has strict regulations on fishing to protect its fish stock. Part of Bob's job is to provide the government with fish mortality data. Today, he has two samples of fish to investigate, sample A and sample B. Bob concluded sample A had natural mortality, but sample B had fishing mortality. 
Question: Would pollution be a casue of death or not a cause of death for sample B?
[A]: not a cause of death.


[Q]: 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 has a higher percentage of limestone in its composition?
[A]: White.


[Q]: Background Paragraph: Enzymes increase the rate of chemical reactions by reducing the amount of activation energy needed for reactants to start reacting. One way this can happen is modeled in the Figure below . Enzymes aren’t changed or used up in the reactions they catalyze, so they can be used to speed up the same reaction over and over again. Each enzyme is highly specific for the particular reaction is catalyzes, so enzymes are very effective. A reaction that would take many years to occur without its enzyme might occur in a split second with the enzyme. Enzymes are also very efficient, so waste products rarely form. 
Story: Keith is a physician with the city hospital. He noticed that reactions inside human body happen in different rates. He specifically noticed two cases, case A and case B. In case A enzymes were present, but in case B enzymes were not present. 
Question: In which case the activation energy needed would be higher, case A or case B?
[A]:
case B.