Other forms: living systems
In biology, a living system is a set of parts that work together to maintain stability and life. Living systems also interact with their environment.
Examples of living systems range from the simplest single-celled organisms to entire ecosystems. There are many living systems inside your own body, including the circulatory system, in which a network of cells and tissues interact to keep your blood flowing and your body alive. In fact, your whole body is a living system that coordinates many smaller subsystems, including cells, tissues, and organ systems. All living systems are biological units that interact with their environment, using energy to maintain internal stability.