The organelle within both plant and animal cells that functions to regulate what can enter or exit a cell.

Its a Membrane-bound organelle, so for your answer you should put, 
"The organelle within both plant and animal cells that functions to regulate what can enter or exit a cell is the Cell membrane.

Ibelieve the answer is a-broad because that is a leafed plant.

Not only is it the purchase of about 40% of america, it also grounds to on-go our advancement as a civilization.