Given the background: 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. and the situation: Large birds are natural predators of rodents. Unfortunately, rodents consume crops in farmlands. In recent years, use of chemicals in agriculture has seen reduced number of large birds in Germany. But in some places in France farmers are cautions about using chemicals in agriculture. As a result, large bird population had been stable in France. Answer the following question: Would France see less or more rodents in agricultural lands than Germany?
Ans: less

Given the background: While people have been able to prevent certain viral diseases by vaccinations for many hundreds of years, the development of antiviral drugs to treat viral diseases is a relatively recent development. Antiviral drugs are medications used specifically for treating the symptoms of viral infections. The first antiviral drug was interferon , a substance that is naturally produced by certain immune cells when an infection is detected. Over the past twenty years the development of antiretroviral drugs (also known as antiretroviral therapy, or ART) has increased rapidly. This has been driven by the AIDS epidemic. and the situation: Two friends had different diseases. Nigel was more prone to viral infections, so one day he got infected with the HIV virus. Manny had contracted some sort of bacterial infection. Answer the following question: Which friend received less interferon?
Ans: Manny

Given the background: You don't have to suffer through an infection to gain immunity to some diseases. Immunity can also come about by vaccination. Vaccination is the process of exposing a person to pathogens on purpose so the person will develop immunity to them. In vaccination, the pathogens are usually injected under the skin. Only part of the pathogens are injected, or else weakened or dead pathogens are used. This causes an immune response without causing the disease. Diseases you are likely to have been vaccinated against include measles, mumps, and chicken pox. and the situation: Two families had children that played together in the park. Jones family were anti-vaxxers, so they never vaccinated against any disease. Dean family did all the required vaccinations. Answer the following question: Which family wasn't vaccinated against mumps?
Ans: Jones

Given the background: Ecology is the study of ecosystems. An ecosystem consists of all the living and nonliving components of the habitat. Whereas nutrients and certain elements are recycled through ecosystems, energy moves in just one direction. Many interactions among species within an ecosystem are centered around the flow of energy. The formation of ecosystems, from new land to current habitats, is usually based on the pioneer species, and these species are able to live in an area due to the nonliving factors, such as the climate, the soil and the amount of rainfall, of that area. The populations within an ecosystem also determine the stability of the system. Recent tremendous increases in the human population have raised many important ecological issues. and the situation: Two friends were into natural sciences. Tom was more into Geology, while Rick studied Ecology. Answer the following question: Which student read more about nonliving components of the habitat?
Ans: Rick