Explanations:A tsunami is a series of ocean waves caused by large-scale disturbances such as earthquakes, landslides, or volcanic eruptions. These waves can travel at high speeds and cause significant damage when they reach the shore. The phenomenon of a tsunami is characterized by several unique signs that can be observed before the actual waves arrive. One of these signs is the unusual movement of the ocean, which can be described as the "moving back" of the ocean. This occurs because the tsunami wave, which is often not visible in the open ocean, causes a significant displacement of water. As the wave approaches the shore, the water level may recede dramatically, exposing the ocean floor and creating a false sense of calm.
Another sign that can be observed before a tsunami is the strange sounds that are produced. These sounds can be described as bird-like noises, which are often caused by the movement of air and water as the tsunami wave approaches. The sound can be quite loud and is often described as a roar or a rumble. This sound is a result of the massive displacement of water and the movement of air as the wave travels through the ocean.
It is important to understand that these signs are specific to tsunamis and are not typically associated with other natural phenomena such as cyclones or rain. Cyclones are characterized by strong winds and heavy rainfall, and while they can cause significant damage, they do not produce the same signs as a tsunami. Rain is a meteorological phenomenon and does not involve the specific oceanic movements or bird-like sounds that are indicative of a tsunami.
Therefore, the correct answer is D) Tsunami, as it is the only option that correctly describes the phenomenon associated with the moving back of the ocean and the production of bird-like sounds. Understanding these signs is crucial for early detection and warning systems, which can help save lives in the event of a tsunami.