Q: What do fission reactors use to slow down the neutrons? Read this paragraph and choose the correct option from the provided answers: U-235 nuclei can capture neutrons and disintegrate more efficiently if the neutrons are moving slower than the speed at which they are released. Fission reactors use a moderator surrounding the fuel rods to slow down the neutrons. Water is not only a good coolant but also a good moderator, so a common type of fission reactor has the fuel core submerged in a huge pool of water. This type of reactor is called a light water reactor or LWR. All public electricity generating fission reactors in the United States are LWRs. Choices: - inertia - brake - control - moderator A:
moderator

Q: A wall of rocks or concrete that juts out into the ocean perpendicular to the shore is called? Read this paragraph and choose the correct option from the provided answers: Longshore drift can erode the sediment from a beach. To keep this from happening, people may build a series of groins. A groin is wall of rocks or concrete that juts out into the ocean perpendicular to the shore. It stops waves from moving right along the beach. This stops the sand on the upcurrent side and reduces beach erosion. You can see how groins work in Figure below . Choices: - shield - rib - fault - groin A:
groin

Q: What property of warm air causes it to rise above cold air? Read this paragraph and choose the correct option from the provided answers: The warm-air vent is placed near the floor of the room. Warm air is less dense than cold air so it rises. If the warm-air vent were placed near the ceiling instead, how would this affect the transfer of thermal energy throughout the room?. Choices: - greater pressure - greater density - higher temperature - lower density A:
lower density