Life, or existence, refers to the condition of being alive, characterized by growth, reproduction, and response to stimuli. It encompasses a wide variety of organisms, including plants, animals, and humans, all of which interact with their environments. Life is sustained by processes such as metabolism, which converts energy from food into usable forms. The study of life is known as biology, which explores the complex systems and relationships that define living organisms. Life exists in diverse forms, from microscopic bacteria to large mammals, each adapted to their specific habitats. Understanding life helps us appreciate the interconnectedness of all living things on Earth.