A cell that can self-renew and differentiate into other cell types. Potency Potency refers to a stem cell's ability to differentiate into different cell types. The more potent a cell is, the more types of cells it can become. Quiescence A dormant, non-dividing state of cells. Senescence Permanent cell growth arrest due to aging or damage. HOX genes HOX genes are a group of genes that determine the body plan and the identity of structures during embryonic development Simplicity A system with few components. Complexity A system with many interconnected parts. Emergence Complex patterns arising at a higher order (or scale) from simpler interactions from a lower order.