What is the bridge between two plant cells made of?

The continuity of cytoplasm from cell to cell is maintained by . . . . . . .

In plants,the cytoplasm of two adjacent cells is connected by .......... .

Select the correct combination of the statements regarding the characteristics of the middle lamella:
$a$. It holds the different neighbouring cells together.
$b$. It is composed of $Mg$ pectate only.
$c$. It gets dissolved during the ripening of fruits.
Correct statements is/are:

What is the nature of the cell wall in terms of permeability?

The mineral constituent of the cell wall is