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: 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: Mike is studying the predator prey relationship. He is specifically studying three species, species A, species B, and species C. Species A is a predator; species B is the prey; and species C is a plant species that species B lives on. Mike now needs to figure out how the predator prey relationship balance the ecosystem. 
Question: If species C population decrease, would it affect the ecosystem positively or negatively?

SOLUTION: negatively.

PROBLEM: 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?

SOLUTION: point B.

PROBLEM: Background Paragraph: Distance decay is a geographical term which describes the effect of distance on cultural or spatial interactions. The distance decay effect states that the interaction between two locales declines as the distance between them increases. Once the distance is outside of the two locales' activity space, their interactions begin to decrease.

With the advent of faster travel, distance has less effect than it did in the past, except where places previously connected by now-abandoned railways, for example, have fallen off the beaten path. Advances in communications technology, such as telegraphs, telephones, broadcasting, and internet, have further decreased the effects of distance.[1]. 
Story: Chad invested massively in railways and highways over the past decade. They also funded many IT projects and telecom infrastructure. On the other hand, Bahrain invested less, and didn't do much to improve communication pathways and technologies between different villages. 
Question: Which country experiences lesser distance decay effect?

SOLUTION:
Chad.