Let's take a look at the diagram for the cell cycle:
Recall that the order is from G1 phase to Telophase, where cells ready to undergo cell division start in interphase.
Let's define our answer choices:
0. Shrinkage of the nucleus
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1. DNA duplication
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2. Cytokinesis
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3. DNA segregation
We are trying to find which of these answer choices occurs before cell division (which is known as mitosis/meiosis depending on the type of cell).
We can see from the cell cycle diagram that the stages before mitosis would be the G2 phase, the S phase, and the G1 phase.
Let's go through each of our answer choices:
0. Shrinkage of the nucleus - this answer choice ,never, happens in the cell cycle. The nucleus ,dissipates, or ,dissolves, away when the cell is ready to undergo mitosis.
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1. DNA duplication - this answer choice is ,correct,. DNA duplication occurs during the ,S phase,, which is ,before, mitosis (cell division).
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2. Cytokinesis - this is when the 2 cells during mitosis split and become 2 separate cells. This would signify the ,end, of mitosis, so this answer ,would not be correct,.
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3. DNA segregation - this answer choice happens ,during, mitosis. Therefore, this answer choice is not correct.
Therefore, our answer choice is B.
