Final answer:
More cells are observed in Interphase than in the M-phase because Interphase is the longest portion of the cell cycle, encompassing cell growth, DNA replication, and preparation for cell division.
Step-by-step explanation:
Observing more cells in Interphase than in the M-phase of the cell cycle is largely due to the fact that Interphase is significantly longer than the M-phase. Interphase consists of three stages: G1, S, and G2. During the G1 phase, the cell grows and accumulates the materials necessary for DNA replication. In the S phase, DNA synthesis occurs, and in the G2 phase, the cell continues to grow and prepare for mitosis. Together, these stages account for most of the cell cycle’s duration, preparing the cell for the far quicker M-phase, where mitosis and cytokinesis occur, resulting in the division of one cell into two daughter cells. Therefore, the chances of observing a cell in Interphase at any given moment are higher than observing it in M-phase, accounting for the greater number of Interphase cells seen under a microscope.