Biological organization

Biological organization refers to how living things are structured in a nested hierarchy, from the smallest units to complex systems. At the simplest level, there are molecules like water and proteins. These combine to form cells, the basic units of life. Cells group together into tissues, such as muscle or skin, which work together to perform specific functions. Tissues form organs like the heart or lungs, part of organ systems like the circulatory or respiratory system. These systems make up an organism—in this case, a human or animal. This organization helps living things grow, reproduce, and maintain homeostasis efficiently.