[Q]: Two related native tribes live thousands of miles away from each other. Ana tribe lives near the South Pole in Antarctica, while Momu tribe lives in Northern Alaska near the North Pole. Which tribe experienced a lower level of UV radiation?
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[A]: Momu

[Q]: John likes to ride on hot air balloon. Last month he rode on a balloon with his friend Keith. First they were at the ground-level. They called it camp A. Then they rose to the height of three miles. They called it camp B. Eventually, they reached six miles above ground. They called it camp C. Would there be less or more oxygen in camp B than in camp C?
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[A]: more

[Q]: Mike is studying the population growth rate of countries around the world. He noticed that countries like Japan and Russia are having a demographic shift. They have a growing population of late adulthood. He recorded the late adulthood population as population A. On the other hand, many developing countries have growing population of younger people. He recorded younger population as population B. Which population would be more at risk of cancer or Alzheimer's disease, population A or population B?
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[A]: population A

[Q]: Twenty first century is seeing an explosion of artificial island building. Many countries are building islands in the middle of seas and oceans, which they often use for tourism or for defensive purposes. For example, UAE had build several islands in the Persian Gulf. To build those islands they had to ask Oman and Qatar to export sand to them. Qatar declined to export sand, but Oman agreed. Oman in turn had to mine huge quantity of sand in their own country. Would coral reef sustain or deteriorate in Qatar?
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[A]:
sustain