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: 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 groups of students studied Biology. Group One studied mammals, while Group Two studied birds. They focused on the respiratory system. 
Question: Which group of students learned more about alveoli?
[EX A]: One.

[EX Q]: Background Paragraph: Candied fruit, also known as crystallized fruit or glacé fruit, has existed since the 14th century. Whole fruit, smaller pieces of fruit, or pieces of peel, are placed in heated sugar syrup, which absorbs the moisture from within the fruit and eventually preserves it. Depending on size and type of fruit, this process of preservation can take from several days to several months.[1] This process allows the fruit to retain its quality for a year.[2]

The continual process of drenching the fruit in syrup causes the fruit to become saturated with sugar, preventing the growth of spoilage microorganisms due to the unfavourable osmotic pressure this creates.[3]. 
Story: Greg's grandma is a culinary expert. She is also  very eager to teach others how to make great foods. One day she taught Greg how to make candied fruit. Greg was so excited about it that he bought two baskets of fruits, basket A and basket B, to make some candied fruits. He used the basket A fruits to make some candied fruits, but was too lazy to use the basket B fruits. He just kept the basket B fruits on his kitchen top. 
Question: Which fruits' moisture would be absorbed from within, basket A fruits or basket B fruits?
[EX A]: basket A fruits.

[EX Q]: Background Paragraph: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution that harms the health of living things. The air pollution also causes acid rain and contributes to global warming. In addition, fossil fuels are nonrenewable resources, so if we keep using them, they will eventually run out. The main advantage of nuclear energy is that it doesn’t release air pollution or cause the other environmental problems associated with the burning of fossil fuels. On the other other hand, radioactive elements are nonrenewable like fossil fuels and could eventually be used up. 
Story: There are two cities, Chien and Marisol, in France that are leaders in the amount of wine they export to the rest of the world. Although they both export the same amount of wine, they use different sources of power to generate their electricity. Chien uses coal to power the city and Marisol uses nuclear power plants to produce electricity. The citizens of both cities are voting on whether to continue their current method of electricity generation. 
Question: Which city has less air pollution?
[EX A]:
Marisol.