Gap 0 phase
The Gap zero or Gap 0 phase is one of the substages of the cell cycle marked by the cell's quiescence, i.e. the cell is neither replicating its DNA nor preparing itself to divide. Cells, such as nerve cells and heart muscle cells, enter Gap 0 phase and become differentiated. Other cells, such as liver and kidney parenchymal cells, may revert to becoming active again and eventually divide through mitosis.