(a) In the control sample histogram, identify the phase of the cell cycle (G1, S, or G2) of the population of cells in each region delineated by vertical lines. Label the histogram with these phases and explain your answer. (b) Does the S phase population of cells show a distinct peak in the histogram? Why or why not?

The cell cycle is a collection of sequential steps by which cells divide to produce two daughter cells. It completes in four phases that are G1, S, G2, and M. G1 is the first phase at which cells do all preparations for division.

In the S phase, the cell replicates its DNA. In the G2 phase, cells are prepared to divide. M phase is a dividing phase.

Cells are inhibited from dividing in interval A when they start their cell cycle. The cell cycle initiates from G1 and then to S, and after it, they reach in G2 phase.So in interval A, G1 is the phase, and interval B indicates the S phase, and C shows the G2 phase.

The cells in the S phase do not show a distinct peak in the histogram because the DNA content varies in each cell as it progresses to divide. Due to different levels of fluorescence in each cell, the peak is not formed distinct.