In this task, you will be presented with a context passage, a question about that paragraph, and a possible answer to that question. The task is to check the validity of the answer. Answer with "Yes" or "No".

[EX Q]: Abrasion is another type of weathering. Like ice wedging, it is a form of mechanical weathering. Like ice wedging, abrasion does not change the rock into another type of rock. With abrasion, one rock or piece of sediment bumps against another rock. Rocks dont normally roll around on their own, so why do they move? There are a couple of reasons a rock may move. Gravity can cause rocks to move. They may roll downhill or fall off a cliff. As they roll down a hill, they bump into each other. Maybe a moving rock hits a rock that is not moving at the bottom of the hill. Moving water causes rocks and sediment to move. Rocks are bounced along the bottom and bump against one another. As they collide, they begin to chip away at each other. Angular rocks become more rounded with each collision. Strong winds cause abrasion. The wind carries sediment. This sediment is thrown against other rocky surfaces by the wind. It is like sand-blasting a rock. <sep>How does gravity cause rocks to move?<sep>They bump into each other
[EX A]: No

[EX Q]: Fossils can be used to match up rock layers. As organisms change over time, they look different. Older fossils will look different than younger fossils. Some organisms only survived for a short time before going extinct. Knowing what organisms looked like at certain times also helps date rock layers. Some fossils are better than others for this use. The fossils that are very distinct at certain times of Earths history are called index fossils. Index fossils are commonly used to match rock layers. You can see how this works in Figure 2.30. If two rock layers have the same index fossils, then they're probably about the same age. <sep>How are fossils used to match up rock layers?<sep>They match the mineral deposits
[EX A]: No

[EX Q]: The cute red ball rolled over to the blue ball and said hello. The blue ball was scared and went to cry to the green ball. The green ball laughed at the blue ball. Then the green ball told the orange ball that blue ball was stupid. Most felt this was not good to do and so they punished the green ball by taking away all his air. From that day on everyone saw the air-less green ball and knew that they could not do or say any bad things. This is how the trouble started. The purple ball used the fear of everyone to become the leader that they all feared. The purple ball was mean to everyone. Until one day the red ball spoke up and got all the other colored balls together and they took the air from the purple ball and put it in the green ball. Sadly, the green ball had been without air for too long and was dead. <sep>Who was the leader the balls feared?<sep>The purple ball
[EX A]:
Yes