The is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell. a) plasma membrane b) nucleoid region c) ribosome d) pili e) cell wall

E) plasma membrane..

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

not sure if this is what you'r looking for nnew= nold