Density-dependent inhibition is a phenomenon in which crowded cells stop dividing at some optimal density and location. this phenomenon involves binding of a cell-surface protein to its counterpart on an adjoining cell's surface. a growth inhibiting signal is sent to both cells, preventing them from dividing. certain external physical factors can affect this inhibition mechanism. select the statement that makes a correct prediction about natural phenomena that could occur during the cell cycle to prevent cell growth. a) as cells become more numerous, they begin to squeeze against each other, restricting their size and ability to allow cell growth. b) as cells become more numerous, the protein kinases they produce begin to compete with each other until only one cell has the proteins necessary for growth. c) as cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth. d) as cells become more numerous, more and more of them enter the synthesis part of the cell cycle and duplicate dna to inhibit cell growth.