Consider two cells: a stomach-lining epithelial cell dividing more than twice a day and a liver cell dividing every year or two. Which cell is likely to be in G0 phase and why?

The correct answer is liver cell is likely to be in G0 phase.

Cells of inner lining of the stomach made of epithelial cells. They are protective in nature. They get damaged and need to be replaced through division. Whereas, liver is made of hepatocytes and once they reached maturity. These cells are not need to be replaced and cell cycle is generally in G0 stage. The G0 phase is a resting phase in the cell cycle. In this phase cells remain in a quiescent state because in G0 phase a cell is neither dividing nor preparing to divide. G0 phase allows cells to become adapted for particular function. Hepatocytes may divide when there is removal of part of liver.