Question: I read this background article the other day: As a young man, Bohr worked in Rutherford's lab in England. Because Rutherford's model was weak on the position of the electrons, Bohr focused on them. He hypothesized that electrons can move around the nucleus only at fixed distances from the nucleus based on the amount of energy they have. He called these fixed distances energy levels, or electron shells. He thought of them as concentric spheres, with the nucleus at the center of each sphere. In other words, the shells consisted of sphere within sphere within sphere. Furthermore, electrons with less energy would be found at lower energy levels, closer to the nucleus. Those with more energy would be found at higher energy levels, farther from the nucleus. Bohr also hypothesized that if an electron absorbed just the right amount of energy, it would jump to the next higher energy level. Conversely, if it lost the same amount of energy, it would jump back to its original energy level. However, an electron could never exist in between two energy levels. These ideas are illustrated in the Figure below . I am facing a new situation today: Greg was studying Bohr's model. He found it helpful to categorize different scenarios in the model. First, he labeled electron with higher energy as cat A, and electron with lower energy as cat B. Then he labeled electron that gained energy as cat C, and election that lost energy as cat D. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which energy level would cat A reside, higher energy level or lower energy level?
Answer: higher energy level

Question: I read this background article the other day: Common foodborne viruses include norovirus and hepatitis A virus. Norovirus, which causes inflammation of the stomach and intestines, has been a recent issue on cruise ships, infecting hundreds of passengers and crew on certain voyages. Hepatitis A causes inflammation of the liver, which is treated with rest and diet changes. Parasites are tiny organisms that live inside another organism. Giardia is a parasite spread through water contaminated with the stools of people or animals who are infected. Food preparers who are infected with parasites can also contaminate food if they do not thoroughly wash their hands after using the bathroom and before handling food. Trichinella is a type of roundworm parasite. People may be infected with this parasite by consuming raw or undercooked pork or wild game. I am facing a new situation today: Two brothers had very bad luck when they attended a wedding. Tom fell violently ill after eating some tainted food, and he was rushed to the hospital. His brother Rob felt sick later, after eating the main course. Tom was infected with norovirus and hepatitis A, while Rob was infected with Giardia and Trichinella. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which brother was not infected by food preparers who didn't wash their hands?
Answer: Tom

Question: I read this background article the other day: Many different chemical substances cause cancer. Dozens of chemicals in tobacco smoke, including nicotine, have been shown to cause cancer ( Figure below ). In fact, tobacco smoke is one of the main sources of chemical carcinogens. Smoking tobacco increases the risk of cancer of the lung, mouth, throat, and bladder. Using smokeless tobacco can also cause cancer. Other chemicals that cause cancer include asbestos, formaldehyde, benzene, cadmium, and nickel. I am facing a new situation today: Two friends met after 20 years. Tom had been smoking tobacco all these years and had some health problems related to that, while Randy quit smoking 25 years ago. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which friend had a higher risk of developing cancer of the throat?
Answer:
Tom