Chlor-zinc iodide ($Schulze's$ solution) stains which of the following?

The cell wall is ........

What is the middle lamella composed of?

Assertion $A$: The middle lamella is present between the primary walls of two adjacent plant cells.
Reason $R$: Two adjacent cells maintain cytoplasmic contact through plasmodesmata.
Which option is correct for Assertion $A$ and Reason $R$?

The plant cell wall is made up of cellulose. This is believed to be

In the middle lamella of plant cell walls,one of the main elements is