Answer:
system
Step-by-step explanation:
All organisms have some sort of biological organization which begins with atoms that join together to form molecules and macromolecules. These atoms and molecules make up the organelles such as mitochondria, nucleus of a cell. Several organelles associate to form a cell which is a basic unit of life
When different cells associate together, they form tissues such as bone tissues. A collection of several tissues makes up an organ such as bone to perform a specific task. Several organs associate to perform body functions. This group of organs is referred to as an organ system. For example, the skeletal system is made up of bones, cartilage, tendons and ligaments. They work together to perform various functions such as movement, creating of red blood cells etc.