instruction:
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.
question:
Background Paragraph: Although some lipids in the diet are essential, excess dietary lipids can be harmful. Because lipids are very high in energy, eating too many may lead to unhealthy weight gain. A high-fat diet may also increase lipid levels in the blood. This, in turn, can increase the risk for health problems such as cardiovascular disease. The dietary lipids of most concern are saturated fatty acids, trans fats, and cholesterol. For example, cholesterol is the lipid mainly responsible for narrowing arteries and causing the disease atherosclerosis. 
Story: Ben and Jerry were two friends with very different dietary habits. Jerry ate healthy food, and was always on top of his caloric consumption, while Ben overate because he loved fatty foods such as butter, bacon et al. 
Question: Which friend had a lower blood lipid level?
answer:
Jerry.


question:
Background Paragraph: There is worldwide concern about the relationship between climate change and the use of fossil fuels. Many scientists believe that increased use of these fuels (in vehicles and other gas-powered equipment) has the potential to irreversibly damage our environment. In addition to the environmental concerns, supplies of fossil fuels are finite, and because they are non-renewable energy sources, we will eventually need alternatives. New developments in batteries and other energy storage devices are being explored to help deal with these issues. Electrochemical processes are at the heart of these new technologies. 
Story: Two countries used different fuels as power sources for their activities. Alsacia used fossil fuels, while Lorena devised more advanced energy storage devices, therefore relying on electricity. 
Question: Which country contributed less to climate change?
answer:
Lorena.


question:
Background Paragraph: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species. 
Story: Two teams studied two types of animals: team A studied predators, while team B studied grazers. They learned a lot from this experience. 
Question: Which team learned that predators play an important role in an ecosystem?
answer:

team A.