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.

[EX Q]: Background Paragraph: Apex predators affect prey species' population dynamics and populations of other predators, both in aquatic and in terrestrial ecosystems. Non-native predatory fish, for instance, have sometimes devastated formerly dominant predators. A lake manipulation study found that when the non-native smallmouth bass was removed, lake trout, the suppressed native apex predator, diversified its prey selection and increased its trophic level. As a terrestrial example, the badger, an apex predator, predates on and also competes with the hedgehog, a mesopredator, for food such as insects, small mammals, reptiles, amphibians and ground-nesting bird's eggs. Removal of badgers (in a trial investigating bovine tuberculosis) caused hedgehog densities to more than double. Predators that exert a top-down control on organisms in their community are often considered keystone species. Humans are not considered apex predators because their diets are typically diverse, although human trophic levels increase with consumption of meat. 
Story: Rob is a biologist who is interested in native species conservation. To that end, he conducted two studies, case A and case B. In case A, a non native apex predator C was introduced in formerly apex predator D's habitat. In case B, same non native apex predator C was removed from formerly apex predator D's habitat. He now needs to analyze the results of these studies. 
Question: Would predator D's trophic level increase or decrease in case B than in case A?
[EX A]: increase.

[EX Q]: Background Paragraph: The balls used in squash are small rubber balls that can differ in terms of diameter, weight and softness. These features determine the speed and bouncing amplitude of the ball, with softer balls being generally slower than the harder balls. The temperature of the ball also affects the amount of bounce: the warmer the ball, the more it bounces.[3] Because cold squash balls have little bounce, the squash balls are hit multiple times at the beginning of a game to warm them up. It also means that a game becomes gradually faster as it advances and that softer balls may be too slow to be used in colder climates.[4]. 
Story: Thomas and Joseph, two experienced squash players, are having a disagreement about which types of squash balls they should use in their match. Both have different preferences for the type of ball used. Joseph prefers a ball that bounces less and travels more slowly. Thomas, on the other hand, prefers a ball that travels more quickly and bounces more. 
Question: Which player enjoys the speed of game more as it progresses?
[EX A]: Thomas.

[EX Q]: Background Paragraph: Anemophilous pollen grains are light and non-sticky, so that they can be transported by air currents. They are typically 20–60 micrometres (0.0008–0.0024 in) in diameter, although the pollen grains of Pinus species can be much larger and much less dense. Anemophilous plants possess well-exposed stamens so that the pollens are exposed to wind currents and also have large and feathery stigma to easily trap airborne pollen grains. Pollen from anemophilous plants tends to be smaller and lighter than pollen from entomophilous ones, with very low nutritional value to insects. However, insects sometimes gather pollen from staminate anemophilous flowers at times when higher-protein pollens from entomophilous flowers are scarce. Anemophilous pollens may also be inadvertently captured by bees' electrostatic field. This may explain why, though bees are not observed to visit ragweed flowers, its pollen is often found in honey made during the ragweed floral bloom. Other flowers that are generally anemophilous are observed to be actively worked by bees, with solitary bees often visiting grass flowers, and the larger honeybees and bumblebees frequently gathering pollen from corn tassels and other grains. 
Story: Two botanists studied different types of plants. Barb studied anemophilous plants, while her friend Faye learned about entomophilous plants. 
Question: Which botanist learned less about well-exposed stamens?
[EX A]:
Faye.