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.
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Question: Background Paragraph: The epidermis also contains melanocytes , which are cells that produce melanin. Melanin is the brownish pigment that gives skin much of its color. Everyone has about the same number of melanocytes, but the melanocytes of people with darker skin produce more melanin. The amount of melanin produced is determined by heredity and exposure to UV light, which increases melanin output. Exposure to UV light also stimulates the skin to produce vitamin D . Because melanin blocks UV light from penetrating the skin, people with darker skin may be at greater risk of vitamin D deficiency. 
Story: Matt and his brother Jesse are twins. They look almost identical. If it weren't for the fact that Jesse has a slightly darker skin complexion you wouldn't be able to tell them apart. In fact one year Matt was out in the sun for a long time and picked up a bit of a tan so they actually did look exactly alike. 
Question: Will an increase in the amount of melanin produced make a person skin darker or lighter?

Answer: darker.


Question: Background Paragraph: Cholesterol has been implicated in heart disease for decades. Atherosclerosis is a disorder of the arteries in which cholesterol and other materials are deposited on the interior of the arterial wall. These deposits lead to the formation of plaques that can restrict or even block the flow of blood through these blood vessels (see Figure below ). A decrease in the flow of blood can lead to high blood pressure and a lowered oxygen supply to the heart muscle. A complete blockage of blood flow to parts of the heart (a heart attack) can cause significant damage due to oxygen deprivation, in some cases leading to death. 
Story: Two groups of patients were under observation for heart disease. The Red group was composed of people with low cholesterol, while the Yellow group was comprised of people with very high cholesterol. 
Question: Which group had fewer people with lowered oxygen supply to the heart muscle?

Answer: Red.


Question: Background Paragraph: People protect areas that might flood with dams. In dire situations, they use sandbags ( Figure below ). Dams are usually very effective, but high water levels sometimes cause a dam to break. In that case, flooding can be catastrophic. Flood waters can also overflow a dam. People may line a river bank with levees to protect against floods. These are high walls that keep the stream within its banks during floods. Flood protection in one location sometimes causes problems elsewhere. For example, a levee in one location may just force the high water upstream or downstream. This will lead to flooding in a different location. Sometimes water gets so high that the river must be allowed to flood. 
Story: Two villages experienced flooding this spring. Berg village used many sandbags to protect from the dam overflowing. Creek village didn't use any sandbags, they were caught by surprise. 
Question: Which village experienced lower water levels?

Answer:
Berg.