Why bryophytes do not attain great heights?

Bryophytes seldom achieve great heights. The possible reasons are:
(a) Absence of roots.
(b) Materials are transportated from cell to cell.
© Absence of vascular tissues.
(d) Absence of cuticle on the plant body.
(e) Requirement of external sheet of water for capillary conduction to all parts and transport of male gametes.