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: A person with a serious brain injury usually suffers permanent brain damage. These brain injuries usually occur when an external mechanical force, such as a violent blow or jolt to the head or body, causes brain dysfunction. An object penetrating the skull, such as a bullet or a shattered piece of the skull, also can cause traumatic brain injury. As a result, the person may have trouble talking or controlling body movements. Symptoms depend on what part of the brain was injured. Serious brain injuries can also cause personality changes and problems with mental abilities such as memory. Medicines, counseling, and other treatments may help people with serious brain injuries recover from, or at least learn to cope with, their disabilities. 
Story: Tammy and Rob rode a tandem bike down the hill. They hit a large rock and fell. Tammy wound up in the hospital and was diagnosed with a serious brain injury. Rob suffered only a mild concussion. 
Question: Which person had fewer problems with mental abilities?
[A]: Rob.


[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: David is investigating the breathing process of different organisms. He found that humans have alveoli to help them with gas exchange. He got curious about other organisms that do not have alveoli. To compare these two groups he labeled organisms with alveoli as group A and organisms without alveoli as group B. 
Question: Would group A have greater or smaller gas exchange than group B?
[A]: greater.


[Q]: Background Paragraph: Distance decay is a geographical term which describes the effect of distance on cultural or spatial interactions. The distance decay effect states that the interaction between two locales declines as the distance between them increases. Once the distance is outside of the two locales' activity space, their interactions begin to decrease.

With the advent of faster travel, distance has less effect than it did in the past, except where places previously connected by now-abandoned railways, for example, have fallen off the beaten path. Advances in communications technology, such as telegraphs, telephones, broadcasting, and internet, have further decreased the effects of distance.[1]. 
Story: Two neighboring countries with similar economies, followed different political and economical agendas. Niger developed its infrastructure and communications technology, while Nigeria didn't. 
Question: Which country experiences a more noticeable distance decay effect?
[A]:
Niger.