Give scientific reasons : Vascular tissues are also called complex tissue.

$\Rightarrow$ In the structure of vascular tissue, structural and functional characteristics of various types of cells are combined. So it is called complex tissue. In xylem tissue, tracheids, vessels, xylem parenchyma and xylem sclerenchyma are included.

$\Rightarrow$ In phloem tissue sieve cells, sieve tube, companion cells, phloem parenchyma and phloem sclerenchyma (fibres) are included.

$\Rightarrow$ Thus it can be said that vascular tissues are complex tissues.