user: Problem: Rob is competing in a cross country race. After running about a mile he reached a place with two signs, sign A and sign B. Sign A says that it's a quicksand. But sign B says that it's not a quicksand. He has to decide which way to go.  Given the paragraph above, please answer correctly the following question:   Which way would have spongy texture, sign A or sign B?  Hint: Quicksand forms in saturated loose sand when the sand is suddenly agitated. When water in the sand cannot escape, it creates a liquefied soil that loses strength and cannot support weight. Quicksand can form in standing water or in upwards flowing water (as from an artesian spring). In the case of upwards flowing water, forces oppose the force of gravity and suspend the soil particles.  The saturated sediment may appear quite solid until a sudden change in pressure or shock initiates liquefaction. This causes the sand to form a suspension and lose strength. The cushioning of water gives quicksand, and other liquefied sediments, a spongy, fluid-like texture. Objects in liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced soil/water mix and the submerged object floats due to its buoyancy.

A: sign A


Problem: Two of Earth's oceans provide vast quantities of fish for human consumption. The Indian ocean hosts a large concentration of phytoplankton blooms in summer. The Pacific ocean has less phytoplankton and nutrients for marine life.  Given the paragraph above, please answer correctly the following question:   Which ocean accounts for a less economically valuable tuna catch?  Hint: Among the tropical oceans, the western Indian Ocean hosts one of the largest concentration of phytoplankton blooms in summer, due to the strong monsoon winds. The monsoonal wind forcing leads to a strong coastal and open ocean upwelling, which introduces nutrients into the upper zones where sufficient light is available for photosynthesis and phytoplankton production. These phytoplankton blooms support the marine ecosystem, as the base of the marine food web, and eventually the larger fish species. The Indian Ocean accounts for the second largest share of the most economically valuable tuna catch. Its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna.Research indicates that increasing ocean temperatures are taking a toll on the marine ecosystem. A study on the phytoplankton changes in the Indian Ocean indicates a decline of up to 20% in the marine phytoplankton in the Indian Ocean, during the past six decades. The tuna catch rates have also declined abruptly during the past half century, mostly due to increased industrial fisheries, with the ocean warming adding further stress to the fish species.Endangered marine species include the dugong, seals, turtles, and whales.An Indian Ocean garbage patch was discovered in 2010 covering at least 5 million square kilometres (1.9 million square miles). Riding the southern Indian Ocean Gyre, this vortex of plastic garbage constantly circulates the ocean from Australia to Africa, down the Mozambique Channel, and back to Australia in a period of six years, except for debris that get indefinitely stuck in the centre of the gyre.The garbage patch in the Indian Ocean will, according to a 2012 study, decrease in size after several decades to vanish completely over centuries.  Over several millennia, however, the global system of garbage patches will accumulate in the North Pacific.In 2016 six new animal...

A: Pacific


Problem: Two farms had different plant cultivation methods. Jolly farm adopted the permaculture methods created by Sepp Holzer, while Peach farm continued using fertilizers and pesticides.  Given the paragraph above, please answer correctly the following question:   Which farm caused more fertilizer to dissolve in rain water?  Hint: Rain dissolves fertilizer in the soil. Runoff carries it away. The fertilizer ends up in bodies of water, from ponds to oceans. Nitrogen is a fertilizer in the water. Since there is a lot of nitrogen, it causes algae to grow out of control. Pictured below is a pond covered with algae ( Figure below ). Algae use up carbon dioxide in the water. After the algae die, decomposers break down the dead tissue. The decomposers use up all the oxygen in the water. This creates a dead zone. A dead zone is an area in a body of water where nothing grows because there is too little oxygen. There is a large dead zone in the Gulf of Mexico ( Figure below ). The U.S. states outlined on the map have rivers that drain into the Gulf of Mexico. The rivers drain vast agricultural lands. The water carries fertilizer from these areas into the Gulf.

A: Peach


Problem: An alien passing by Earth in a UFO to write a report on two random cities so that his government can better understand what the people of Earth are like. He first flies over Nillmar, a city in France, which uses burns coal as its main production of electricity. After observing Nillmar, the alien flies over to Springfield, a city in the United States, that decided to use nuclear power to fuel itself. After taking his notes, the alien leaves and is eager to report back to his superiors about what he discovered.  Given the paragraph above, please answer correctly the following question:   Which city will need to change its method of electricity production sooner?  Hint: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy.

A:

assistant: Springfield