Final answer:
Cells in the root meristem are often in interphase, a stage of the cell cycle that is much longer than mitosis, where cells grow and prepare for cell division.
Step-by-step explanation:
Many of the cells of the root meristem are not undergoing mitosis; rather, they are in a stage called interphase. Based upon the interpretations made above, interphase appears to be much longer than mitosis. During interphase, the cell undergoes normal growth processes while also preparing for cell division, which includes the three phases G1, S, and G2. G1 Phase is a period of growth and accumulation of energy, S Phase is for the synthesis of DNA, and G2 involves the preparation for mitosis. The short period of intense mitotic activity contrasts sharply with the much longer duration of interphase, which is sometimes mistakenly thought to be a 'quiet' time for the cell.