During which step of the cell cycle does a cell get a signal to begin cell division?

Prophase

Explanation:

Prophase is not only the first step of Mitosis and Meiosis (I and II), but it is crucial because it helps the chromatin become chromosomes, this is after Interphase where DNA replication occurs this is the signal that starts the dividing process. This phase also helps with condensing the chromosomes which acts as another signal to division because the chromosomes are prepared to be separated from one another. Spindle fibers (microtubules) are also created to get ready for separation. Now that these main things happened during Prophase, it signifies the rest of the cell and the other phases occur.

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not sure if this is what you'r looking for nnew= nold

the answer is d p: cell, q: organ, r: organ system, s: tissue