Question: Q: The surfaces of the bones at the joints are covered with a smooth layer of cartilage, which reduces what force between the bones when they move? Read this paragraph and choose the correct option from the provided answers: Movable joints allow the greatest movement and are the most common. In these joints, the bones are connected by ligaments. The surfaces of the bones at the joints are covered with a smooth layer of cartilage. It reduces friction between the bones when they move. The space between the bones is also filled with a liquid called synovial fluid. It helps to cushion the bones. There are several different types of movable joints. You can see three of them in Figure below . Move these three joints in your own skeleton to experience the range of motion each allows. Choices: - vibration - expulsion - gravity - friction A:
Answer: friction

Question: Q: When do weather balloons return to earth? Read this paragraph and choose the correct option from the provided answers: Weather stations contain many instruments for measuring weather conditions. The weather balloon ( Figure above ) will rise into the atmosphere until it bursts. As it rises, it will gather weather data and send it to the surface. Many weather satellites orbit Earth. They constantly collect and transmit weather data from high above the surface. A radar device sends out radio waves in all directions. The waves bounce off water in the atmosphere and then return to the sender. The radar data shows where precipitation is falling. It's raining in the orange-shaded area shown above. Choices: - when the air heats up - when the timer runs out - when the air cools - when it bursts A:
Answer: when it bursts

Question: Q: How does deeper material cause convection in the mantle? Read this paragraph and choose the correct option from the provided answers: Not long after Wegener's death, scientists recognized that there is convection in the mantle. Deeper material is hotter and so it rises. Near the surface, it becomes cooler and denser so it sinks. This creates a convection cell in the mantle. Choices: - remains stable - folds - sinks then rises - rises then sinks A:
Answer:
rises then sinks