Organisation
The Hierarchy of Organisation
Cells are the basic building blocks of all living organisms, and they are organised into progressively larger, more complex levels. Each level builds on the last: cells form tissues, tissues form organs, organs form organ systems, and organ systems work together to form the whole organism.
Cell → Tissue → Organ → Organ System → Organism
Example
A single muscle cell joins with other muscle cells to form muscle tissue; this tissue combines with other tissues to form the stomach, which is part of the digestive system – a key organ system in the human organism.