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: Soil is well developed in the forest as suggested by the thick humus layers, rich diversity of large trees and animals that live there. In forests, precipitation exceeds evapotranspiration which results in an excess of water that percolates downward through the soil layers. Slow rates of decomposition leads to large amounts of fulvic acid, greatly enhancing chemical weathering. The downward percolation, in conjunction with chemical weathering leaches magnesium (Mg), iron (Fe), and aluminum (Al) from the soil and transports them downward, a process known as podzolization. This process leads to marked contrasts in the appearance and chemistry of the soil layers. 
Story: Two  brothers were land owners. Bill owned 40 acres of forest, , with very well developed soil. His brother Rick owned 40 acres of grasslands, with a poor soil. Rick decided to sell his land. 
Question: Which brother owned a land which had slow rates of decomposition?

A: Bill.
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Q: Background Paragraph: For comparison,  sunlight on Saturn is slightly brighter than Earth sunlight at the average sunset or sunrise (see daylight for comparison table). Even on Pluto, the sunlight would still be bright enough to almost match the average living room. To see sunlight as dim as full moonlight on Earth, a distance of about 500 AU (~69 light-hours) is needed; there are only a handful of objects in the Solar System known to orbit farther than such a distance, among them 90377 Sedna and (87269) 2000 OO67. 
Story: A startup has build a simple spaceship that uses only sunlight for its propulsion. The more sunlight it gets faster it moves. They planned to send the spaceship to three different points, point A, point B, and point C. Point A is near the planet Saturn, point B is near Pluto, and point C is about 69 light-hours away. 
Question: At which point the spaceship would move faster, point B or point C?

A: point B.
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Q: Background Paragraph: New species develop naturally through the process of natural selection . Due to natural selection, organisms with traits that better enable them to adapt to their environment will tend to survive and reproduce in greater numbers. Natural selection causes beneficial heritable traits to become more common in a population and unfavorable heritable traits to become less common. For example, a giraffe’s neck is beneficial because it allows the giraffe to reach leaves high in trees. Natural selection caused this beneficial trait to become more common than short necks. 
Story: There is a creature called a Brotor that has inhabited the planet Glarknon for thousands of years. The Brotor have two distinct traits on them, but each Brotor only has one of these traits. The vast majority of Brotors have fins on their body, but there is a very small segment of the Broto population that has arms instead of fins. 
Question: Which trait has been developed by natural selection?

A:
fins.
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