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.

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 keystone species?
Kim.

Background Paragraph: Gibberellins are hormones that cause the plant to grow. When gibberellins are applied to plants by scientists, the stems grow longer. Some gardeners or horticulture scientists add gibberellins to increase the growth of plants. Dwarf plants (small plants), on the other hand, have low levels of gibberellins ( Figure below ). Another function of gibberellins is to stop dormancy (resting time) of seeds and buds. Gibberellins signal that it’s time for a seed to germinate (sprout) or for a bud to open. 
Story: Keith has four plants in his backyard, plant A, plant B, plant C, and plant D. Plant A is very large, but plant B is smaller. Plant C and D are the same size. He applied some gibberellins to plant C, but didn't apply anything to plant D. He got curious about why some plants are bigger, while others are not. 
Question: Which plant would see increase in growth, plant C or plant D?
plant C.

Background Paragraph: The Gaia hypothesis states that the biosphere is its own living organism. The hypothesis suggests that the Earth is self-regulating and tends to achieve a stable state, known as homeostasis . For example the composition of our atmosphere stays fairly consistent, providing the ideal conditions for life. When carbon dioxide levels increase in the atmosphere, plants grow more quickly. As their growth continues, they remove more carbon dioxide from the atmosphere. In this way, the amount of carbon dioxide stays fairly constant without human intervention. 
Story: A scientist with an interesting idea for an experiment begins building a dome. This dome will be completely cut off from the rest of the world. It will produce all of its own resources, breathable air, anything needed to sustain life, putting it into a state of homeostasis. 
Question: Given the dome experiment is a success will carbon dioxide levels increase, or stay fairly consistent?

consistent.