Given the task definition and input, reply with output. 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".

When a stream or river slows down, it starts dropping its sediments. Larger sediments are dropped in steep areas. Some smaller sediments can still be carried by a slow moving stream or river. Smaller sediments are dropped as the slope becomes less steep. Alluvial Fans In arid regions, a mountain stream may flow onto flatter land. The stream comes to a stop rapidly. The deposits form an alluvial fan. Deposition also occurs when a stream or river empties into a large body of still water. In this case, a delta forms. A delta is shaped like a triangle. It spreads out into the body of water. <sep>When are deltas formed?<sep>When large deposits are dropped in steep areas

No