Identify $P, Q,$ and $R$ in the given figure.

$A$: Cells of sclerenchyma have thickened secondary walls.
$R$: Cells have deposition of lignin.

Parenchyma is:

Protoxylem and metaxylem are components of which of the following?

Given below are two statements:
Statement $I$: Parenchyma is living but collenchyma is dead tissue.
Statement $II$: Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of angiosperms.
In the light of the above statements,choose the correct answer from the options given below:

Collenchyma differs from parenchyma in