TASK DEFINITION: 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.
PROBLEM: 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: John studies how chemicals affect environment. He traveled to the Amish country to see their traditional ways of farming. He noticed they don't use any fertilizers or pesticides. He labeled this part of the study as case A. Then he visited a modern farming facility where they use tons of fertilizers and pesticides. He labeled this part of the study as case B. 
Question: Would case B see more or less growth of algae than case A?

SOLUTION: more.

PROBLEM: Background Paragraph: We all enjoy a cool dip in a swimming pool on a hot day, but we may not realize the work needed to keep that water safe and healthy. The ideal pH for a swimming pool is around 7.2. The pH will change as a result of many factors. Adjustment can be accomplished with different chemicals depending on the tested pH. High pH can be lowered with liquid HCl (unsafe material) or sodium bisulfate. The bisulfate anion is a weak acid and can dissociate partially in solution. To increase pH, use sodium carbonate. The carbonate anion forms an equilibrium with protons that results in some formation of carbon dioxide. 
Story: Tom and John are both pool owners. Tom prefers to use sodium bisulfate in his pool because he enjoys the smell. John, however, prefers using sodium carbonate in his pool because he believes it helps keep pests away. 
Question: Whose pool will have a lower pH?

SOLUTION: Tom.

PROBLEM: Background Paragraph: Iron is first oxidized to iron(II) ions by oxygen. In the second step, the iron(II) ions are further oxidized and combine with water and oxygen gas to produce a hydrated form of iron(III) oxide known as rust. Rusting is one of many example of corrosion. Corrosion is the deterioration of metals by redox processes. Corrosion causes enormous amounts of damage to buildings, bridges, ships, cars, and other objects. It has been estimated that corrosion costs the U.S. economy over 100 billion dollars each year. A great amount of time and effort is spent to try to limit or prevent corrosion. 
Story: Jordan is conducting an experiment to see how Iron rusts. He first takes Iron Bar A and puts it out on his porch on a rainy day. Then he puts Iron bar B in an airtight bag and removes all of the oxygen and air to vacuum seal it. After some time passes the bar he left outside is completely covered in rust. He removes the bar in the vacuum sealed bag and to his surprise it has no rust at all. Because there was no oxygen and water in the air tight bag, iron bar B has no rust at all. Iron bar A was exposed to a lot of water and oxygen and there for it rusted completely. 
Question: Which iron bar was exposed to more water and oxygen, Iron Bar A or Iron Bar B?

SOLUTION:
Iron Bar A.