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: Pollutants also affect the atmosphere through their contribution to global warming. Global warming is an increase in the Earth’s temperature. It is thought to be caused mostly by the increase of greenhouse gases like carbon dioxide. Greenhouse gases can be released by factories that burn fossil fuels. Over the past 20 years, burning fossil fuels has produced about three-quarters of the carbon dioxide from human activity. The rest of the carbon dioxide in the atmosphere is there because of deforestation, or cutting down trees ( Figure below ). Trees absorb carbon dioxide during cellular respiration, so when trees are cut down, they cannot remove carbon dioxide from the air. 
Story: Long island was full of people and they used all their natural resources and burned fossil fuels while Snail island protected the environment and had fewer people living there. 
Question: Which island contributed more to global warming?
[A]: Long.


[Q]: Background Paragraph: Sand mining is a direct cause of erosion, and impacts the local wildlife.[2] Various animals depend on sandy beaches for nesting clutches, and mining has led to the near extinction of gharials (a species of crocodile) in India. Disturbance of underwater and coastal sand causes turbidity in the water, which is harmful for organisms like coral that need sunlight. It can also destroy fisheries, financially harming their operators.

Removal of physical coastal barriers, such as dunes, sometimes leads to flooding of beachside communities, and the destruction of picturesque beaches causes tourism to dissipate. Sand mining is regulated by law in many places, but is often done illegally.[3] Globally, it is a $70 billion industry, with sand selling at up to $90 per cubic yard.[4]. 
Story: Sand mining in the north coastal region was stopped 20 years ago, but it still continues to this day in the south region. Both fishing communities there are still prosperous, but the southern one had a couple of bad years, with fish and other marine wildlife becoming more scarce. The southern beach had erosion problems as well. The northern beach recovered, and is suitable for tourism. 
Question: Which region has a higher water turbidity?
[A]: southern.


[Q]: Background Paragraph: The example of someone having a positive experience with a drug is easy to see how drug dependence and the law of effect works. The tolerance for a drug goes up as one continues to use it after having a positive experience with a certain amount the first time.[38] It will take more and more to get that same feeling. This is when the controlled substance in an experiment would have to be modified and the experiment would really begin. The law of work for psychologist B. F. Skinner almost half a century later on the principles of operant conditioning, "a learning process by which the effect, or consequence, of a response influences the future rate of production of that response.[39]. 
Story: The Boat Ballers met to discuss their experiences. They all said they always had a great experience using boat and used the same amount each time. They told how many times they used boat. Les used it 99 times, Osvaldo used it 89 times, Dino used it 79 times, Refugio used it 69 times, Coleman used it 59 times, Margarito used it 49 times, and Alden used it 39 times. 
Question: Who has a higher tolerance for boat: Refugio or Osvaldo?
[A]:
Osvaldo.