Problem: Background: Rainfall in an area is important because it influences the rate of weathering. More rain means that more rainwater passes through the soil. The rainwater reacts chemically with the particles. The top layers of soil are in contact with the freshest water, so reactions are greatest there. High rainfall increases the amount of rock that experiences chemical reactions. High rainfall may also carry material away. This means that new surfaces are exposed. This increases the rate of weathering.  Paragraph: Two students at the Agricultural Institute studied pedology. Bob studied soil weathering, while Dan studied types of soil.  Given the paragraph above, please answer correctly the following question: Which student studied more about rock that experiences chemical reactions?

A: Bob


Problem: Background: Allergy symptoms can range from mild to severe. Mild symptoms might include itchy eyes, sneezing, and a runny nose. Severe symptoms can cause difficulty breathing, which may be life threatening. Keep in mind that it is the immune system and not the allergen that causes the allergy symptoms. Allergy symptoms can be treated with medications such as antihistamines. Severe allergic reactions may require an injection of the hormone epinephrine. These treatments lessen or counter the immune system’s response.  Paragraph: Two groups of students went on a field trip. Group Scouts visited a bee farm, while group Bears went to a salmon hatchery. Group Scouts had children experiencing mild allergic reactions, while one student had severe allergic reactions to a bee sting.  Given the paragraph above, please answer correctly the following question: Which group had more students experiencing itchy eyes?

A: Scouts


Problem: Background: Many respiratory diseases are caused by pathogens. A pathogen is an organism that causes disease in another organism. Certain bacteria, viruses, and fungi are pathogens of the respiratory system. The common cold and flu are caused by viruses. The influenza virus that causes the flu is pictured below ( Figure below ). Tuberculosis, whooping cough, and acute bronchitis are caused by bacteria. The pathogens that cause colds, flu, and TB can be passed from person to person by coughing, sneezing, and spitting. Illnesses caused by bacteria can be treated with antibiotics. Those caused by viruses cannot.  Paragraph: The doctors studied two groups of people, group one which included people with respiratory diseases caused by viruses, and group two, which had people with respiratory diseases caused by bacteria.  Given the paragraph above, please answer correctly the following question: Which group didn't include people that had the common cold?

A: group two


Problem: Background: 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.  Paragraph: 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.  Given the paragraph above, please answer correctly the following question: Which sample would more likely be used as fuel, sample C or sample D?

A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
sample D