As we all know, the ocean moves. But waves breaking on the beach make the ocean fun. When you stand on the shore and look at the waves, it seems like the water is moving towards you. But the water is not really moving forward. The moving you see is wave energy. And wave energy comes from the wind. Let's think about how this works. As wave energy passes through the water, the energy makes particles   of water move up and down. Just give you an example of a wave passing under a basketball. We put a basketball on the sea. When the wind blows, a wave comes from behind the basketball. The basketball moves up to the top with the wave. Then the wave continues and leaves the basketball behind. The basketball looks lower, but it doesn't move forward. That's because the wave energy just moves the water which is under the basketball. So why can you see a wave knock you down on the shore?When a wave moves toward the shore, the bottom of the wave slows down because _ meets the ocean floor. But the top, which is called crest , keeps moving. The different action causes the wave to fall over or break onto the shore. If a wave is very large, it carries a lot of energy when it hits the land. As time goes by, waves can break up and carry away the rocks and other things on the shore. Shorelines are changing all the time because of wave action. The main idea of this passage is   _  .
what makes particles of water move how a basketball moves on the ocean how wave energy causes wave action why a wave can knock you down