Write one function each of following

Write one function each of following
(i) Sieve tubes (ii)Xylem (iii) Sclereids

(i) Sieve tubes are used for longitudinal transmission of prepared food materials from the leaves to the storage organs in both downward and upward direction.
(ii) Xylem takes part in the upward conduction of water and solutes.
(iii) Sclereids provide hardness and mechanical strength to the plant organ.