Q. Tracheids are less efficient than vessels due to :

Q. Tracheids are less efficient than vessels due to :

(a) Absence of closed end walls.

(b) Uneven thickenings.

(c) Casparian strips .

(d) Presence of tapering end walls.

Solution :

Correct option : D 
Tracheids differ in many ways from vessels:- (i) Tracheids have narrow lumen while vessels lumen is wide. (ii) Tracheids have less number of large pits while vessels have a large number of small pits.(iii)Tracheids are imperforated while vessels are perforated. (iv) Tracheids have tapering ends while vessels have diagonal or transverse end walls.(v)Tracheids have thin walls while vessels have a thick cell wall . So the correct option is ‘Presence of tapering end walls’.