Vessels differ from tracheids
In being derived from single cell
In having vertical rows of cells with cross walls dissolved
In being living
They help in the conduction of water
Which tissue performs mechanical function in hydrophytic plants
$A$ : Cells of sclerenchyma have thickened secondary walls.
$R$ : Cells have deposition of lignin.
The chief water conducting elements of xylem in gymnosperms are
Fibres associated with phloem are...... .fibres.