Which of the following is $NOT$ found in the composition of the plant cell wall?

Which of the following is not a function of the cell wall?
$(i)$ Provides shape to the cell.
$(ii)$ Protects the cell from mechanical damage and infection.
$(iii)$ Helps in cell-to-cell interaction.
$(iv)$ Provides a barrier to undesirable macromolecules.

Elementary fibrils of cellulose are also known as

The middle lamella is primarily composed of which substance?

Cell wall is absent in

$A$ protoplast is a cell that is: