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: Huge amounts of chemicals, such as fertilizers and pesticides, are applied to farm fields (see Figure below ). Some of the chemicals are picked up by rainwater. Runoff then carries the chemicals to nearby rivers or lakes. Dissolved fertilizer causes too much growth of water plants and algae. This can lead to dead zones where nothing can live in lakes and at the mouths of rivers. Some of the chemicals can infiltrate into groundwater. The contaminated water comes up in water wells. If people drink the polluted water, they may get sick. 
Story: Two neighboring counties used different agricultural methods on their farm fields. Cook county used many fertilizers and pesticides, while Dane county used only organic methods and no pesticides. As a result, the waters in Dane county were cleaner. 
Question: Which county contaminated fewer water wells?
[A]: Dane.


[Q]: Background Paragraph: In nature, when the population size is small, there is usually plenty of food and other resources for each individual. When there is plenty of food and other resources, organisms can easily reproduce, so the birth rate is high. As the population increases, the food supply, or the supply of another necessary resource, may decrease. When necessary resources, such as food, decrease, some individuals will die. Overall, the population cannot reproduce at the same rate, so the birth rates drop. This will cause the population growth rate to decrease. 
Story: Bill studied two herds of deer for a year. He was in love with nature. He observed the large herd named Alpha inhabited an area with fewer resources. Herd Beta was a smaller one, and they grazed on an abundance of plants. 
Question: Which herd had more food available for each individual?
[A]: Beta.


[Q]: Background Paragraph: Baker's yeast is the common name for the strains of yeast commonly used in baking bread and bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ethanol. Baker's yeast is of the species Saccharomyces cerevisiae,[1] and is the same species (but a different strain) as the kind commonly used in alcoholic fermentation, which is called brewer's yeast.[2] Baker's yeast is also a single-cell microorganism found on and around the human body. 
Story: Ken is a microbiologist. He got two samples of yeasts, yeast A and yeast B, from two different businesses. Yeast A is used in a bakery, and yeast B is used in a brewery. He has to decide the characteristics of each 
yeast sample for further study.
Interestingly, despite all his curiosity, Ken doesn't like any yeast to be around him. 
Question: If Ken wants a dough sample to expand, which yeast should he use, yeast A or yeast B?
[A]:
yeast A.