Final answer:
The surface-to-volume ratio does not serve as a signal for cell division.
Step-by-step explanation:
The correct answer is D) surface-to-volume ratio.
Surface-to-volume ratio is not a signal for cell division. It is a physical property that describes the relationship between the surface area of a cell and its volume. This ratio is important for determining how efficiently a cell can exchange materials with its environment, but it does not directly regulate cell division.
In contrast, repressor genes, joining of cyclins and Cdks, and contact inhibition are all signals that regulate cell division. Repressor genes can inhibit the expression of genes involved in cell division. Cyclins and Cdks are proteins that form complexes and activate various cell cycle checkpoints to ensure proper cell division. Contact inhibition is a phenomenon where cells stop dividing when they come into contact with neighboring cells, preventing overgrowth.