The organelle labelled by which alphabet is absent in animal cells?

Which substance is present in the middle lamella of a cell which holds or glues the different neighboring cells together?

Which one is not a component of a normal 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.

What are plasmodesmata?

Robert Hooke discovered the . . . . . . of a cell.