Organs are composed of tissues, which are composed of cells. this is an example of which characteristic of life?

This is an example of Biological organization.

 Biological organization is a hierarchical organization of biological structures and their systems.
Each level of this hierarchy, the complexity increases and it's composed by the previous level's basic unit.
So a cell is the smallest and basic unit.
Tissue is more complexed that cells and it's composed by a lot of cells.
Organs are more complexed that tissues and are composed by tissues