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.

Q: Background Paragraph: About 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. 
Story: White mountains are often visited by tourists because of the many beautiful caves, stalactites, stalagmites and karst phenomena. Dome mountains are interesting to tourists because they are very massive, of volcanic origin and excellent for climbing. 
Question: Which mountain is made of less soluble rock?

A: Dome.
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Q: Background Paragraph: There was no additional air in the tire the second time Lawrence checked the air pressure, but something did change between the two measurements. The tires had rolled over 10 miles of road on the trip to school. Any time one surface moves over another, it causes friction. Friction is a force that opposes the motion of two surfaces that are touching, and friction between two surfaces always generates heat. Quickly rub your hands together and you’ll feel the heat generated by the friction between them. As the tires moved over the road, friction between the tires and road generated heat. In short, the tires got warmer and so did the air inside them. 
Story: There was a carnival game at the fair that allowed you to win a basketball if you could correctly guess which of the two balls had spun around a circular track more times. Each ball would be dropped into identical circular tracks and then a curtain would cover them. Ball A would then spin around the track a certain amount of times, and Ball B would spin around a certain amount of times. After they were done spinning, you had to guess which ball completed more revolutions. A boy came up and had no idea how to figure out the answer, but when he picked them up he noticed that Ball A was slightly warmer than Ball B. 
Question: Which ball completed more revolutions?

A: Ball A.
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Q: Background Paragraph: Blue ice occurs when snow falls on a glacier, is compressed, and becomes part of the glacier. Air bubbles are squeezed out and ice crystals enlarge, making the ice appear blue.

Small amounts of regular ice appear to be white because of air bubbles inside them and also because small quantities of water appear to be colourless. In glaciers, the pressure causes the air bubbles to be squeezed out, increasing the density of the created ice. Large quantities of water appear to be blue, as it absorbs other colours more efficiently than blue. A large piece of compressed ice, or a glacier, similarly appears blue. 
Story: Mike likes to visit places. This winter he is visiting Greenland. First, he visited Lake A, which is very small. Then he visited Lake B, which is huge. While visiting Lake B he went to a local pub. There he heard other tourists talking about two nearby glaciers, glacier C and glacier D. They said that glacier C had a snowfall and the snow became part of the glacier, but glacier D didn't have any snowfall. Mike is getting ready to visit those glaciers. 
Question: Is ice thinner or denser in glacier D than in glacier C?

A:
thinner.
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