Final answer:
Both prokaryotes and eukaryotes utilize the plasma membrane to regulate the passage of substances and ribosomes for protein synthesis.Hence, option A is the correct answer.
Step-by-step explanation:
In both prokaryotes and eukaryotes, the plasma membrane plays a crucial role in regulating the passage of substances in and out of the cell. It acts as a selective barrier, allowing certain molecules to enter or leave the cell while preventing others from doing so. The ribosomes in both types of cells are responsible for protein synthesis, where they translate the genetic information from the DNA into proteins.