The middle lamella is primarily composed of:

$A$ protoplast is:

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 $R$?

Cell wall is absent in

Which of the following determines the shape of the cells and provides a strong structural support to prevent the bacterium from bursting or collapsing?

$RBC$ and a plant cell (with thick cell wall) are placed in distilled water. The solute concentration is the same in both the cells. What changes would be observed in them?