Differentiate between :
(a) Hypocotyl and epicotyl
(b) Coleoptile and coleorhiza

Explanation

(a) The portion of embryonal axis above the cotyledon is called epicotyl, while the portion of embryonal axis below the cotyledon is called hypocotyl.
(b) Coleoptile is a conical protective sheath over the plumule, while coleorhiza is a protective sheath over the root tip in monocotyledonous seeds.