An animal is a living organism that belongs to the kingdom Animalia. Animals are characterized by several features, including being multicellular, heterotrophic (meaning they obtain their food by consuming other organisms), and having the ability to move (at least at some stage of their life cycle). They typically have specialized cells, tissues, and organs, and most have nervous and muscular systems that allow for complex behaviors.
Animals can be classified into various groups based on shared characteristics, including mammals, birds, reptiles, amphibians, fish, and invertebrates. They inhabit diverse environments, ranging from oceans and forests to deserts and polar regions. Animals play essential roles in ecosystems, including pollination, decomposition, and being part of the food web.