user: Problem: Given the question: I read this background article the other day: Electromagnetic radiation is energy that travels in waves across space as well as through matter. Most of the electromagnetic radiation on Earth comes from the sun. Like other waves, electromagnetic waves are characterized by certain wavelengths and wave frequencies. Wavelength is the distance between two corresponding points on adjacent waves. Wave frequency is the number of waves that pass a fixed point in a given amount of time. Electromagnetic waves with shorter wavelengths have higher frequencies and more energy.  I am facing a new situation today: David is experimenting with electromagnetic waves. He has four different waves to study, wave A, wave B, wave C, and wave D. In wave A, distance between two corresponding points on adjacent waves is greater than that of wave B. In wave C, the number of waves that pass a fixed point in a given time is greater than that of wave D.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which wave has higher frequency, wave C or wave D?
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The answer is:
wave C


Problem: Given the question: I read this background article the other day: This is how ice wedging works. When liquid water changes into solid ice, it increases in volume. You see this when you fill an ice cube tray with water and put it in the freezer. The ice cubes go to a higher level in the tray than the water. You also may have seen this if you put a can of soda into the freezer so that it cools down quickly. If you leave the can in the freezer too long, the liquid expands so much that it bends or pops the can. (For the record, water is very unusual. Most substances get smaller when they change from a liquid to a solid.)  I am facing a new situation today: Jeremy is performing some chores around the kitchen when he decides to pour himself some water into a blue cup. However, this water isn't cold enough so he puts it into the freezer to cool it down. He then pours himself the exact same amount of water in a red cup, but gets a phone call and leaves that cup on the table without taking a sip. He comes back two hours later after the phone call to get his cups of water back.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Will the water in the red or blue cup have less volume?
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The answer is:
red


Problem: Given the question: I read this background article the other day: The earliest members of the human species evolved around 200,000 years ago in Africa. Early humans lived in small populations of nomadic hunters and gatherers. Human beings remained in Africa until about 40,000 years ago. After that, they spread throughout Europe, Asia, and Australia. By 10,000 years ago, the first human beings colonized the Americas. During this long period of time, the total number of human beings increased very slowly. Birth rates were fairly high but so were death rates, producing low rates of population growth.  I am facing a new situation today: Archaeologists studied data about human settlements. One was 100,000 years old called village R, and the other one was about 9,000 years old called village N. The older settlement was located in Africa, the other one wasn't.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which village had more people that were gatherers?
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The answer is:


assistant: village R