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.

[EX Q]: Background Paragraph: Iron is first oxidized to iron(II) ions by oxygen. In the second step, the iron(II) ions are further oxidized and combine with water and oxygen gas to produce a hydrated form of iron(III) oxide known as rust. Rusting is one of many example of corrosion. Corrosion is the deterioration of metals by redox processes. Corrosion causes enormous amounts of damage to buildings, bridges, ships, cars, and other objects. It has been estimated that corrosion costs the U.S. economy over 100 billion dollars each year. A great amount of time and effort is spent to try to limit or prevent corrosion. 
Story: Aaron is doing a science experiment for school. He is trying to see what happens to different iron objects in different conditions. He has two samples that he is testing. Sample A he has placed in a dark dry room away from the elements. Sample B he has placed outside under no cover, so it will be rained on. 
Question: Will Sample B be more or less likely to show signs of corrosion compared to Sample A?
[EX A]: more.

[EX Q]: Background Paragraph: Often, foreign exchange controls can result in the creation of black markets to exchange the weaker currency for stronger currencies. This leads to a situation where the exchange rate for the foreign currency is much higher than the rate set by the government, and therefore creates a shadow currency exchange market. As such, it is unclear whether governments have the ability to enact effective exchange controls.[1]. 
Story: On March 2015 Japans economy soared. There was a likelihood that the Japanese yen would rise in value. In the wake of this event, Japanese Government adjusted 
the price of Japanese Currency Yen in accordance with the going market price. On the other hand, at he same time, UK was having economic downturn. There was a likelihood that the UK Currency Pound Sterling would go down. Fearing public backlash, UK Government kept the price of the Pound Sterling at the same level. 
Question: Which Government took the wrong step to combat their currency being traded in the black market?
[EX A]: UK Government.

[EX Q]: Background Paragraph: Groundwater salinization compromises buffering properties. Vegetation clearance, along with irrigation, causes serious issues. Irrigation increases the water table and mobilizes salts, and vegetation clearance allows it to come in contact with water habitats and vegetation. This stresses species not adapted to high salinity. High levels of salinity reduces water uptake in plants, by causing stomatal closure, reducing photosynthesis. Forests undergo decline in areas of high salinity and shallow groundwater depths because these conditions make them more susceptible to droughts. Forests undergo decline in areas of high salinity and shallow groundwater depths making them more susceptible to droughts. 
Story: In the sixteenth century the State of Michigan had forests all over. But that has long been gone. 
Especially, in the state's northeast part the vegetation has been cleared in the twentieth century. 
Wooded areas were replaced by farm lands. All these farmlands were under heavy Irrigation. At one time, in the sixteenth century, plant species like elm and oak used to be plentiful. We still had some elms and oaks in the twentieth century, but they were not great many in number. 
Question: Was the mobilized salts at increased or decreased level in northeast Michigan in the sixteenth century?
[EX A]:
decreased level.