Here's a breakdown:

* Cell wall: This is the outermost layer of the Elodea cell, providing structural support and protection.

* Plasma membrane: This thin, flexible layer lies directly beneath the cell wall. It's a selectively permeable barrier that controls what enters and exits the cell.

Think of it like a house with a fence around it. The fence is the cell wall, providing protection, and the house itself is the cell, with the plasma membrane acting as the door that regulates what goes in and out.