Given the background: Look at the police car in Figure below . The sound waves from its siren travel outward in all directions. Because the car is racing forward (toward the right), the sound waves get bunched up in front of the car and spread out behind it. As the car approaches the person on the right (position B), the sound waves get closer and closer together. In other words, they have a higher frequency. This makes the siren sound higher in pitch. After the car speeds by the person on the left (position A), the sound waves get more and more spread out, so they have a lower frequency. This makes the siren sound lower in pitch. A change in the frequency of sound waves, relative to a stationary listener, when the source of the sound waves is moving is called the Doppler effect . You've probably experienced the Doppler effect yourself. The next time a vehicle with a siren races by, listen for the change in pitch. For an online animation of the Doppler effect, go to the URL below. and the situation: John was sitting at point C near a railway track. Suddenly, he heard a train coming towards him from point A with constant sound of its horn. Eventually, it reached very close to him at point B. Then the train sped by him at point C where he was sitting, reaching point D after some time. Finally, it reached even farther from him at point E. Answer the following question: Which point would have lower frequency, point D or point E?
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Answer: point E

Q: Given the background: Recall that air pollution is due to chemical substances and particles released into the air mainly by human actions. When most people think of air pollution, they think of the pollution outdoors. But it is just as easy to have indoor air pollution. Your home or school classroom probably doesn't get much fresh air. Sealing up your home reduces heating and cooling costs. But this also causes air pollution to stay trapped indoors. And people today usually spend a majority of their time indoors. So exposure to indoor air pollution can become a significant health risk. and the situation: Patty was a runner and liked hiking so she spent a lot of time outdoors. Her friend Fay sealed up her home and spent most of her time indoors. Both friends lived in an area with moderate to high levels of air pollution and attended a seminar where they learned more about the impact of air pollution on human health. Answer the following question: Which friend was exposed to less outdoor pollution?
A: Fay

Question: Given the background: Because the gravitational field created by the Moon weakens with distance from the Moon, it exerts a slightly stronger than average force on the side of the Earth facing the Moon, and a slightly weaker force on the opposite side. The Moon thus tends to "stretch" the Earth slightly along the line connecting the two bodies. The solid Earth deforms a bit, but ocean water, being fluid, is free to move much more in response to the tidal force, particularly horizontally. As the Earth rotates, the magnitude and direction of the tidal force at any particular point on the Earth's surface change constantly; although the ocean never reaches equilibriumthere is never time for the fluid to "catch up" to the state it would eventually reach if the tidal force were constantthe changing tidal force nonetheless causes rhythmic changes in sea surface height. and the situation: Mike was reading about an instrument that could measure gravity, gravimeter. He then found how gravimeter was used to measure the gravitational field of the Moon. He read about two distinct cases where the Moon's gravitational field was measured on earth, side A and side B. In side A the Moon's gravity was measured from the side where the Earth was facing the Moon. And in side B the Moon's gravitational field was measured from the opposite side of the Earth. He found these two locations showed very different consequences of Moon's gravitational field. Answer the following question: On which side the Moon's gravitational field would exert weaker force, side A side B?
Answer: side B

[Q]: Given the background: When the temperature of reactants is higher, the rate of the reaction is faster. At higher temperatures, particles of reactants have more energy, so they move faster. As a result, they are more likely to bump into one another and to collide with greater force. For example, food spoils because of chemical reactions, and these reactions occur faster at higher temperatures (see the bread on the left in the Figure below ). This is why we store foods in the refrigerator or freezer (like the bread on the right in the Figure below ). The lower temperature slows the rate of spoilage. and the situation: Justin and Thomas are two college students conducting an experiment in their chemistry laboratory course. They are mixing together acids and bases to produce sodium based compounds. Justin conducts his reactions at a high temperature, while Thomas conducts his reactions at a lower temperature. Answer the following question: Whose reactions will occur at a faster rate?
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[A]: Justin

input: Please answer the following: Given the background: Soil piping is a particular form of soil erosion that occurs below the soil surface. It causes levee and dam failure, as well as sink hole formation. Turbulent flow removes soil starting at the mouth of the seep flow and the subsoil erosion advances up-gradient. The term sand boil is used to describe the appearance of the discharging end of an active soil pipe.Soil salination is the accumulation of free salts to such an extent that it leads to degradation of the agricultural value of soils and vegetation. Consequences include corrosion damage, reduced plant growth, erosion due to loss of plant cover and soil structure, and water quality problems due to sedimentation. Salination occurs due to a combination of natural and human-caused processes. Arid conditions favour salt accumulation. This is especially apparent when soil parent material is saline. Irrigation of arid lands is especially problematic. All irrigation water has some level of salinity. Irrigation, especially when it involves leakage from canals and overirrigation in the field, often raises the underlying water table. Rapid salination occurs when the land surface is within the capillary fringe of saline groundwater. Soil salinity control involves watertable control and flushing with higher levels of applied water in combination with tile drainage or another form of subsurface drainage. and the situation: The city of Lampo is currently experiencing some soil piping in the ground. The government officials of Lampo are currently looking to start a casino to bring in extra revenue to the town. They are currently consulting with a company that is located in Himpton, a city that is not experiencing soil piping. The company is a well respected leader in the casino industry and is eager to work with Lampo. Answer the following question: Are sink holes more or less likely to form in Lampo?
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output: more

Given the background: While people have been able to prevent certain viral diseases by vaccinations for many hundreds of years, the development of antiviral drugs to treat viral diseases is a relatively recent development. Antiviral drugs are medications used specifically for treating the symptoms of viral infections. The first antiviral drug was interferon , a substance that is naturally produced by certain immune cells when an infection is detected. Over the past twenty years the development of antiretroviral drugs (also known as antiretroviral therapy, or ART) has increased rapidly. This has been driven by the AIDS epidemic. and the situation: Bob was a medical student and he studied drugs administered to people with viral diseases, while his colleague Liam decided to study other types of drugs, such as antibiotics and anticoagulants. Answer the following question: Which colleague studied less about interferon?
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Answer:
Liam