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: The lungs of mammals are unique in having alveoli . These are tiny, sac-like structures. Each alveolus is surrounded by a network of very small blood vessels (see Figure below ). Because there are millions of alveoli in each lung, they greatly increase the surface area for gas exchange between the lungs and bloodstream. Human lungs, for example, contain about 300 million alveoli. They give the lungs a total surface area for gas exchange of up to 90 square meters (968 square feet). That’s about as much surface area as one side of a volleyball court!. 
Story: Two friends read about respiratory systems. Paul read more about the lungs of mammals, while Pete read more about the lungs of frogs. 
Question: Which student read more about gas exchange between the lungs and bloodstream?
Paul.

Background Paragraph: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy. 
Story: Marion county used coal and oil to produce electricity, while James county used nuclear energy for its electricity production. Both counties had a flourishing economy. 
Question: Which county caused more air pollution?
Marion.

Background Paragraph: Storing large volumes of data – When storing XML to either file or database, the volume of data a system produces can often exceed reasonable limits, with a number of detriments: the access times go up as more data is read, CPU load goes up as XML data takes more power to process, and storage costs go up. By storing XML data in Fast Infoset format, data volume may be reduced by as much as 80 percent. 
Story: Porfirio had a busy day storing XML. At 9 AM, he stored 203 Gigabytes to the database. At 10 AM, he stored 303 Gigabytes to the database. At 11 AM, he stored 403 Gigabytes to the database. At 12 PM, he got lunch. At 1 PM, he stored 503 Gigabytes to the database. At 2 PM, he stored 603 Gigabytes to the database. At 3 PM, he went to sleep to finish storing XML later that night. 
Question: What time did storage costs go up:  9 AM or 3 PM?

9 AM.