Problem: Given the question: John is a nuclear scientist who works at the Fermi lab. Today, in front of him he has four samples, sample A, sample B, sample C, and sample D. Sample A is the naturally occurring uranium. Sample B is enriched uranium. Sample C is the U-238, and sample D is the U-235. He needs to figure out how to best use them. Which sample would have lower percentage of uranium-235, sample A or sample B? Hint: Naturally occurring uranium is composed almost entirely of two isotopes, uranium-238 (99%) and uranium-235 (1%). It is the uranium-235 that is fissionable (will undergo fission) and therefore, this is the uranium isotope than can be used for fuel in a nuclear reactor. For uranium to be used as fuel, the percent of uranium-235 must be increased to at least 3%. Uranium in which the U-235 content is more than 1% is called enriched uranium. Somehow, the two isotopes must be separated so that enriched uranium is available for use as fuel. Separating the isotope by chemical means (chemical reactions) is not successful because the isotopes have exactly the same chemistry. The only essential difference between U-238 and U-235 is their atomic masses; as a result, the two isotopes are separated by a physical means that takes advantage of the difference in mass.
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The answer is:
sample A

Problem: Given the question: The Farlook forest is classified as a tropical forest, and the Celeste forest is not a tropical forest. Jessica is currently looking for a forest to go camping in and is trying to choose which of these two forests she will visit for a week. Jessica despises camping in the rain and also prefers a more moderate temperature. Luckily, her trip isn't for several months so she has plenty of time to make up her mind. Which forest should Jessica not go camping in? Hint: Tropical forests (rainforests) receive more insolation and rainfall over longer growing seasons than any other environment on earth. With these elevated temperatures, insolation and rainfall, biomass is extremely productive leading to the production of as much as 800 grams of carbon per square meter per year. Higher temperatures and larger amounts of water contribute to higher rates of chemical weathering. Increased rates of decomposition cause smaller amounts of fulvic acid to percolate and leach metals from the zone of active weathering. Thus, in stark contrast to soil in forests, tropical forests have little to no podzolization and therefore do not have marked visual and chemical contrasts with the soil layers. Instead, the mobile metals Mg, Fe and Al are precipitated as oxide minerals giving the soil a rusty red color.
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The answer is:
Farlook

Problem: Given the question: Two cousins went for a blood test. Tim found out he had hemophilia, while John was normal. Tim had to start taking medication. Which cousin has a lack of clotting factors in the blood? Hint: Hemophilia is the name of a group of hereditary diseases that affect the body's ability to control blood clotting. Hemophilia is caused by a lack of clotting factors in the blood. Clotting factors are normally released by platelets. Since people with hemophilia cannot produce clots, any cut can put a person at risk of bleeding to death. The risk of internal bleeding is also increased in hemophilia, especially into muscles and joints. This disease affected the royal families of Europe.
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The answer is:
Tim