Problem: Background: The Human Immunodeficiency Virus ( HIV ) is the virus that causes Acquired Immunodeficiency Syndrome ( AIDS ). Most researchers believe that the HIV originated in sub-Saharan Africa during the 20th century. HIV is transmitted by sexual contact and by contact with infected bodily fluids, such as blood, semen, breast milk, and vaginal secretions. It is also passed from mother to fetus. HIV is now a pandemic , with an estimated (as of 2008) 38.6 million people now living with the disease worldwide. It is estimated that AIDS has killed more than 25 million people since it was first recognized in 1981. For further information about HIV/AIDS, see the CDC (Centers for Disease Control and Prevention) web site at http://www.cdc.gov/hiv/resources/factsheets/ . Paragraph: Dean and Paul both went to volunteered in Africa. They had a blood test when they came back. Paul had been infected with the HIV virus while Dean was healthy and clean. Given the paragraph above, please answer correctly the following question: Which friend has a virus that causes Acquired Immunodeficiency Syndrome?

A: Paul

Problem: Background: 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. Paragraph: 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. Given the paragraph above, please answer correctly the following question: Which brother was infected by consuming undercooked pork?

A: Rob

Problem: Background: Electronic ear protectors work differently. They identify high-amplitude sound waves and send sound waves through them in the opposite direction. This causes destructive interference with the waves, which reduces their amplitude to zero or nearly zero. This changes even the loudest sounds to just a soft hiss. Sounds that people need to hear, such as the voices of co-workers, are not interfered with in this way and may be amplified instead so they can be heard more clearly. This type of hearing protector is recommended for higher noise levels and situations where it's important to be able to hear lower-decibel sounds. Paragraph: Ken and Jen are both attending an air show at a festival today. In each seat at the air show are a pair of electronic ear protectors. Ken puts his on prior to the show starting, but Jen forgets to wear hers and the show begins. Given the paragraph above, please answer correctly the following question: Whose sound waves are being interfered with?

A: Ken

Problem: Background: In the long term, the greatest changes in the Solar System will come from changes in the Sun itself as it ages. As the Sun burns through its supply of hydrogen fuel, it gets hotter and burns the remaining fuel even faster. As a result, the Sun is growing brighter at a rate of ten percent every 1.1 billion years. In about 600 million years, the Sun brightness will have disrupted the Carbon Cycle to the point that trees and forests (C3 photosynthetic plant life) will no longer be able to survive and in around 800 million years, the Sun will have killed all complex life on the Earth's surface and in the oceans. In 1.1 billion years' time, the Sun's increased radiation output will cause its circumstellar habitable zone to move outwards, making the Earth's surface too hot for liquid water to exist there naturally. At this point, all life will be reduced to single celled organisms. Evaporation of water, a potent greenhouse gas, from the oceans' surface could accelerate temperature increase, potentially ending all life on Earth even sooner. During this time, it is possible that as Mars's surface temperature gradually rises, carbon dioxide and water currently frozen under the surface regolith will release into the atmosphere, creating a greenhouse effect that will heat the planet until it achieves conditions parallel to Earth today, providing a potential future abode for life. By 3.5 billion years from now, Earth's surface conditions will be similar to those of Venus today. Paragraph: Rob knows a brilliant scientist who has made a time machine. One day, the scientist let Rob travel time with his machine. Rob noticed that the machine had four gears, gear A, gear B, gear C, and gear D. Rob started with Gear A, which represented the present time. Then he pushed the gear to gear B, which was 600 million years from now. Then he further pushed the gear to gear C, which brought him to 800 million years from now. Finally, he pushed the gear to gear D, which brought him to 1.1 billion years from now. Though he traveled time, Rob was always on Earth all the time. Given the paragraph above, please answer correctly the following question: When Rob would see more plant species, gear A or gear B?

A:
gear A