Flow cytometry is a powerful tool for cell cycle analysis. Cells are stained with a fluorescent DNA binding dye that labels the cells based on DNA content. Cells with twice the amount of DNA are therefore twice as bright. The image shows the results of a flow cytometry analysis in a population of cells after they were treated with a new drug over different time points to examine its effect on the cell cycle. The cell populations are shown as histograms, with fluorescence intensity plotted on the x$-$axis and the number of cells with a particular fluorescence intensity plotted on the Y$-$axis. Based on these results, what conclusion can you draw about the drug's effect on cell cycle? Provide a rationale for your assertion.