Whale
As an AI language model, I do not have personal opinions, but to answer the question, a whale is a large marine mammal belonging to the order Cetacea. There are two types of whales: baleen and toothed. Baleen whales, such as humpback whales and blue whales, feed on small marine organisms using baleen plates to filter food from seawater. Toothed whales, such as killer whales and sperm whales, feed on larger prey with their teeth.
As to "why it is," whales are a vital component of marine ecosystems, playing a significant role in the food chain as top predators and helping to regulate populations of prey species. They also contribute to the cycling of nutrients in the ocean and help to maintain healthy oceans. Additionally, whales have cultural and economic importance, as they have been hunted for their meat, oil, and other products for centuries. Today, many countries have laws in place to protect whales from hunting and other threats.