Which ones among the following are corect?
(a)Uneven thickening of cell wll is characteristic of sclerenchyma
(b)periblem forms acortex of stem and root
(c )Tracheids are chief water conduting elements in gymnosperms
(d) Commerical cork is obtained from quercus suber
A. b,c
B. a,d
C. b,e
D. c,d
