Why are xylem and phloem called complex tissues? Write their components.

Xylem and phloem are called complex tissues as they are made up of more than one type of cells and they work as a unit.

(i) Xylem components are tracheids, vessels, xylem fibre and xylem parenchyma.

(ii) Phloem components are sieve tubes, companion cells, phloem parenchyma & phloem fibres.