Question

in the text area below compare and contrast a cell membrane and cell wall.

Explanation:

Cell membrane is a thin, flexible layer made of lipids and proteins. It is found in all cells (plant, animal, prokaryotic). Its functions include regulating substance entry/exit (selective permeability), cell - cell recognition, and signal transduction.
Cell wall is a rigid structure. In plants, it's made of cellulose; in fungi, chitin; in bacteria, peptidoglycan. It is mainly in plant cells, fungal cells, and prokaryotic cells (not in animal cells). Its functions are providing structural support, maintaining cell shape, and protecting against mechanical stress and osmotic pressure.
Both cell membrane and cell wall are at the cell's periphery. They play roles in protecting the cell (cell membrane from harmful substances via selective permeability; cell wall from physical damage). They also interact with the external environment (cell membrane in sensing signals; cell wall in cell - cell adhesion in some cases).

Answer:

Cell membrane: thin, flexible, lipid - protein layer, in all cells, selective permeability, cell - cell recognition, signal transduction.
Cell wall: rigid, composition varies (cellulose - plants, chitin - fungi, peptidoglycan - bacteria), in plant/fungal/prokaryotic cells (not animal), structural support, shape maintenance, protection.
Commonalities: at cell periphery, protective roles, interact with external environment.