Fibres are obtained from

$I.$ These tissues are found as layers or patches.
$II.$ It consists of cells which are thickened at the corners.
$III.$ It often contains chloroplasts.
$IV.$ Intercellular spaces are absent.
$V.$ They provide mechanical support to growing parts of plants.
The above characters are attributed to:

Cells of permanent tissue are $...........$.

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

Which of the following lacks protoplasm at maturity?

From both phylogenetic and ontogenetic points of view,which tissue is regarded as the most primitive?