Problem: 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: Karen studied animals in school. She started studying predators for a school presentation. She liked it. Her friend Molly liked cows, sheep and other herbivores, so she decided to do a presentation about grazers, and their role in nature. Answer the following question: Which girl learned less about animals that keep grass from growing out of control?

A: Karen

Problem: Given the background: Since AM fungi are biotrophic, they are dependent on plants for the growth of their hyphal networks. Growing a cover crop extends the time for AM growth into the autumn, winter, and spring. Promotion of hyphal growth creates a more extensive hyphal network. The mycorrhizal colonization increase found in cover crops systems may be largely attributed to an increase in the extraradical hyphal network that can colonize the roots of the new crop (Boswell et al. 1998). The extraradical mycelia are able to survive the winter, providing rapid spring colonization and early season symbiosis (McGonigle and Miller 1999). This early symbiosis allows plants to tap into the well-established hyphal network and be supplied with adequate phosphorus nutrition during early growth, which greatly improves the crop yield. and the situation: Ted had two farmlands. Hill land had good mycorrhizal colonization because ted used cover crops, while Meadow land had fewer AM fungi present in the soil. Answer the following question: Which land had a more extensive hyphal network.?

A: Hill

Problem: Given the background: During May, June, and July, the Northern Hemisphere is exposed to more direct sunlight because the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere while December, January, and February are the warmest months in the Southern Hemisphere. and the situation: Bill has a friend that lives in New Zealand and he always gets confused about the weather and the seasons when they chat, because the Southern Hemisphere has different seasons than people from the Northern Hemisphere. Answer the following question: Which hemisphere is exposed to more direct sunlight in June?

A: Northern

Problem: Given the background: Hemophilia is the name of a group of hereditary diseases that affect the body's ability to control blood clotting. Hemophilia is caused by a lack of clotting factors in the blood. Clotting factors are normally released by platelets. Since people with hemophilia cannot produce clots, any cut can put a person at risk of bleeding to death. The risk of internal bleeding is also increased in hemophilia, especially into muscles and joints. This disease affected the royal families of Europe. and the situation: Czar Nicholas was the last Romanov who ruled Russia. Al along he was in good health, but that was not the case with his son Prince Alexei. While Nicholas was free from hemophilia, a disease that devastated European royal families, Alexei was born with hemophilia. Many suggest this situation made some opportunists to take advantage of the Czar. Answer the following question: Who would have more clotting factors in the blood, Nicholas or Alexei?

A:
Nicholas