Two students from the same class, studies different types of animals. Bill studied predators, while John studied grazers. Given the paragraph above, please answer correctly the following question: Which student found out that grazers on a grassland keep grass from growing out of control? Hint: 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.
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Answer: John

A pharmaceutical company is trying to find the cure for allergy. To that end, they conducted an experiment with two groups of subjects, group A and group B. They exposed the participants in group A to allergen, but they didn't expose the participants in group B to any allergen. The symptoms of these two groups would help them find the cure for allergy. Given the paragraph above, please answer correctly the following question: In which group the immune system would make inflammatory response, group A or group B? Hint: An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen . Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin. Two common causes of allergies are shown in Figure below . Inhaling ragweed pollen may cause coughing and sneezing. Skin contact with oils in poison ivy may cause an itchy rash. Other common causes of allergies include dust mites, mold, animal dander, insect stings, latex, and certain food and medications. Symptoms of a common allergy such as pollen can include sneezing, a runny nose, nasal congestion and itchy, watery eyes.
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Answer: group A

Two different rivers were stocked with adult fish. Red river had a lower fish population because the fish had hardly reproduced naturally. Black river had doubled it's fish population in two years because they reproduced naturally. Given the paragraph above, please answer correctly the following question: Which of the two rivers had fewer female fish release very high numbers of eggs to increase the chances of fertilization? Hint: Fish reproduce sexually. They lay eggs that can be fertilized either inside or outside of the body. In most fish, the eggs develop outside of the mother's body. In the majority of these species, fertilization also takes place outside the mother's body. The male and female fish release their gametes into the surrounding water, where fertilization occurs. Female fish release very high numbers of eggs to increase the chances of fertilization.
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Answer:
Red