Problem: I have a new situation: 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. But I can use this background: 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. What is an answer for this question: In which way Rob would not sink, sign A or sign B?

A: sign B

Problem: I have a new situation: Marco is sitting at the bottom of a mountain and painting a picture of it. Lauren, Marco's friend, is sitting about halfway up the mountain and painting a picture of the horizon. The two will compare paintings after they complete their drawings and then will switch places and repeat the task. These two friends do this a couple times a year, and they always enjoy seeing how the other person paints the same object. But I can use this background: As shown here, pressure decreases to less than 25% of ground-level atmospheric pressure when we get to an altitude of about six miles. Since this is a common cruising altitude for commercial airplanes, pressurized cabins are needed for the comfort and survival of the passengers. This is because the density of the air decreases along with the decreasing air pressure, so there is less oxygen in a breath of air. You've probably noticed this effect in high-mountain areas, as it often feels harder to breath. What is an answer for this question: Is the air by Lauren more or less dense than the air by Marco?

A: less

Problem: I have a new situation: Two biologists studied different living creatures. Matt studied protozoa, while his friend Greg studied nematodes and insects. But I can use this background: Protozoa generally feed by engulfing and digesting other organisms. As consumers, they have various roles in food chains and webs. Some are predators. They prey upon other single-celled organisms, such as bacteria. In fact, protozoa predators keep many bacterial populations in check. Other protozoa are herbivores. They graze on algae. Still others are decomposers. They consume dead organic matter. There are also parasitic protozoa that live in or on living hosts. For example, the protozoan that causes malaria lives inside a human host. For their part, protozoa are important food sources for many larger organisms, including insects and worms. What is an answer for this question: Which friend studied more about predatory protozoa keeping bacterial populations in check?

A: Matt

Problem: I have a new situation: John was studying the plate tectonics of earth. He specifically selected two locations, location A and location B. He noticed that location A had lot of plate tectonics activities, but location B didn't have much of that. He wondered how that would make difference in those locations' characteristics. But I can use this background: Earth is a restless planet. Heat in the Earth's interior causes giant plates of crust to move around on the surface. The crashing and smashing of these plates leads to nearly all of the geological activity we see. Plate collisions bring us volcanoes and earthquakes, mountain ranges, and many resources. Seafloor forms as plates move apart. Some of Earth's most beautiful landscapes come from plate tectonics. The Grand Tetons in Wyoming rose up as the Farallon Plate sunk beneath the North American Plate during the Laramide orogeny. What is an answer for this question: Which location would have less volcanoes and earthquakes, location A or location B?

A:
location B