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 many ways, bacterial metabolism provides traits that are useful for ecological stability and for human society. One example is that some bacteria have the ability to fix nitrogen gas using the enzyme nitrogenase. This environmentally important trait can be found in bacteria of most metabolic types listed above. This leads to the ecologically important processes of denitrification, sulfate reduction, and acetogenesis, respectively. Bacterial metabolic processes are also important in biological responses to pollution; for example, sulfate-reducing bacteria are largely responsible for the production of the highly toxic forms of mercury (methyl- and dimethylmercury) in the environment. Non-respiratory anaerobes use fermentation to generate energy and reducing power, secreting metabolic by-products (such as ethanol in brewing) as waste. Facultative anaerobes can switch between fermentation and different terminal electron acceptors depending on the environmental conditions in which they find themselves. 
Story: Brett and Scott were both studying bacteria for their exam. Scott read more about nitrogen-fixating and sulfate-reducing bacteria, while his colleague Brett read more about non-respiratory anaerobe bacteria and facultative anaerobes. 
Question: Which student read more about denitrification?

Answer: Scott.


Question: Background Paragraph: Because of human activities, there is more carbon dioxide in the atmosphere today than in the past hundreds of thousands of years. Burning fossil fuels and has released great quantities of carbon dioxide into the atmosphere. Cutting forests and clearing land has also increased carbon dioxide into the atmosphere because these activities reduce the number of autotrophic organisms that use up carbon dioxide in photosynthesis. In addition, clearing often involves burning, which releases carbon dioxide that was previously stored in autotrophs. 
Story: Two cities had different energy source. Big city burned fossil fuels cut forests and cleared land, while Blue city used alternative sources of energy. 
Question: Which city cleared fewer lands?

Answer: Blue.


Question: Background Paragraph: One of the most adverse impacts of poor waste management, especially municipal waste, is the incidence and prevalence of diseases such as malaria and respiratory problems, as well as other illnesses through the contamination of ground water. Biomedical wastes pose great danger in Bangladesh too as a report estimated that 20% of the biomedical waste is "highly infectious" and is a hazard since it is often disposed of into the sewage system or drains.[6]  Such poor sanitation has serious consequences for the health of the residents and a report suggests that "most of the child mortality could be related with this problem".[7]  With regards to the living standards, solid waste leads to blockage in the drainage system which leads to flooding in the streets. Consequently, mosquitoes and bad odour are among the negative impacts resulted.[7]. 
Story: Calgary has just installed a new waste management system in the city, and has been writing new laws about how biomedical research should be properly disposed of. Detroit on the other hand, just passed a law that allows dumping of medical waste in the sewage system, and has cut funding to it's waste management system. 
Question: Which city probably has a lower chance of contaminated ground water?

Answer:
Calgary.