Complex tissues are

In angiosperms,where are the sieve plates located?

The sclerenchyma of the hypodermis in the $Pinus$ needle helps in:

$A$ : Sieve tubes and companion cells are related ontogenetically.
$R$ : Both develop from same mother cell.

Which of the following tissues provides mechanical support to the growing parts of the plant such as the petiole of a leaf and young stem?

Which of the following structures is absent in primary phloem?