A. is your correct answer.
Explanation:
The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.
J-shape curve
J-shape curve is a curve that shows the population density of an organisms as they increase rapidly in a logarithmic or exponential form but abruptly stops due to environmental resistance. Thus, the population rate is largely determined by the biotic potentials and size of the population. However, exponential growth produces J-shaped curve.
RNA begins the process of transcription