He observes the formation of a cell plate. He is observing the phase of the cell cycle Cytokinesis.
Mitosis is used to produce daughter cells that are genetically identical to the parent cells which produces two daughter cells from one parent cell, during it division,shorter cell cycles occur in early embryo cells this later result to the daughter cells been smaller than the mother cell in the embryonic cell cycles
Thus, option "A" is correct.
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