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.

Background Paragraph: Protozoa generally feed by engulfing and digesting other organisms. As consumers, they have various roles in food chains and webs. Some are predators. They prey upon other single-celled organisms, such as bacteria. In fact, protozoa predators keep many bacterial populations in check. Other protozoa are herbivores. They graze on algae. Still others are decomposers. They consume dead organic matter. There are also parasitic protozoa that live in or on living hosts. For example, the protozoan that causes malaria lives inside a human host. For their part, protozoa are important food sources for many larger organisms, including insects and worms. 
Story: Two biologists studied different living creatures. Matt studied protozoa, while his friend Greg studied nematodes and insects. 
Question: Which friend studied less about predatory protozoa?
Greg.

Background Paragraph: Regions on the Earth's surface (or in its atmosphere) that are high above mean sea level are referred to as high altitude. High altitude is sometimes defined to begin at 2,400 meters (8,000 ft) above sea level.[5][6][7]

At high altitude, atmospheric pressure is lower than that at sea level. This is due to two competing physical effects: gravity, which causes the air to be as close as possible to the ground; and the heat content of the air, which causes the molecules to bounce off each other and expand.[8]. 
Story: There was a competition for who can get their yellow kite the highest into the air. Team V got it 3,355 ft. Team W got it 4,455 ft. Team X go it 5,555 ft. Team Y got it 6,635 ft. Team Z got it 11,625 ft. Team A got it 14,775 ft. Team B got it 15,885 ft. 
Question: What team got their kite into high altitude: Team W or Team Z?
Team Z.

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 C than in glacier D?

denser.