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: 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 students studied animal behavior for the biology class. Ned studied more about predators, while Kim studied more about herbivores. 
Question: Which student studied less about keeping grass from growing out of control?
answer:
Ned.


question:
Background Paragraph: Bernoulli’s law explains how the wings of both airplanes and birds create lift that allows flight (see Figure below ). The shape of the wings causes air to flow more quickly — and air pressure to be lower — above the wings than below them. This allows the wings to lift the plane or bird above the ground against the pull of gravity. A spoiler on a race car, like the one in Figure below , works in the opposite way. Its shape causes air to flow more slowly — and air pressure to be greater — above the spoiler than below it. As a result, air pressure pushes the car downward, giving its wheels better traction on the track. 
Story: Rob is experimenting with how air pressure works. To that end, he has designed two tests. In the first test the air flow works as it would in an airplane wing. He labels it as case A. In the second test the air flow works as it would in a race car spoiler. He labels it as case B. He is surprised to see that air flow behaves differently in different situations. 
Question: Would case A have faster or slower air flow above it than case B?
answer:
faster.


question:
Background Paragraph: The general trend in electronegativity is that the value increases from left to right across a row in the periodic table and decreases down a column. The most electronegative element is fluorine, which has a value of 4.0. As discussed in the lesson "Trends in the Periodic Table," electronegativity increases across a row as the number of protons in the nucleus increases and therefore has a stronger pull. Electronegativity decreases down a column due to an increased effect of electron shielding in larger atoms. 
Story: A high school student, Timmy, is reading about elements of a periodic table. He is studying the periodic table when he decides to compare two random elements within the same column. He chooses Mardine and Sampline to compare and contrast and gets to work. The first thing he notices is that Sampline is further down the periodic table than Mardine. It's not much information to go on, but it's a good starting point for Timmy. 
Question: Which element has less electronegativity?
answer:

Sampline.