You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.
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Question: Background Paragraph: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution that harms the health of living things. The air pollution also causes acid rain and contributes to global warming. In addition, fossil fuels are nonrenewable resources, so if we keep using them, they will eventually run out. The main advantage of nuclear energy is that it doesn't release air pollution or cause the other environmental problems associated with the burning of fossil fuels. On the other other hand, radioactive elements are nonrenewable like fossil fuels and could eventually be used up.
Story: The U.S. produces its energy using fossil fuels, while Germany uses nuclear power plants as their main energy source. The two countries impact the environment in different ways.
Question: Which country contributes more to global warming?

Answer: The U.S.

Question: Background Paragraph: Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their "black body" emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths. For example, the Sun is approximately 6,000 K (5,730 C; 10,340 F), its radiation peaks near 500 nm, and is visible to the human eye. Earth is approximately 290 K (17 C; 62 F), so its radiation peaks near 10,000 nm, and is much too long to be visible to humans. The light that is observed on photographs of earth from space and with the naked eye is only reflected visible light.
Story: There are two rocks that scientists are looking at. Rock A is located near the lava stored in an active volcano, and rock B is outside this volcano near the base of it. The scientists are currently trying to find a way to safely transport both rocks back to a lab so they can get these rocks under a microscope to look at them. However, they are currently struggling to figure out an effective way to lift rock A out of the volcano.
Question: Which rock emits less radiation?

Answer: rock B.

Question: Background Paragraph: Storing large volumes of data When storing XML to either file or database, the volume of data a system produces can often exceed reasonable limits, with a number of detriments: the access times go up as more data is read, CPU load goes up as XML data takes more power to process, and storage costs go up. By storing XML data in Fast Infoset format, data volume may be reduced by as much as 80 percent.
Story: Lavern had a stressful day storing a ton of XML. In the morning, he filled up a hard drive with XML. In the afternoon, he filled up a few hard drives with XML. At night, he filled up many hard drives with XML.
Question: What time did the CPU load go up the most: morning or night?

Answer:
night.