Which among the following constituents of xylem is/are tubular structure(s)?_x005F_x000D_ Â _x005F_x000D_ I. Tracheids_x005F_x000D_ II. Vessels_x005F_x000D_ III. Xylem fibres_x005F_x000D_

Which among the following constituents of xylem is/are tubular structu

1.	Which among the following constituents of xylem is/are tubular structure(s)?_x005F_x000D_ Â _x005F_x000D_ I. Tracheids_x005F_x000D_ II. Vessels_x005F_x000D_ III. Xylem fibres_x005F_x000D_
A.	Only I
B.	Only II
C.	Only I and II
D.	All I, II and III
Answer» D. All I, II and III