The characteristic feature of porous wood is represented by the presence of .........

The combination of phelloderm,phellogen,and phellem is collectively known as ..........

In which region are the most distinct annual rings formed?

In old trees,the greater part of secondary xylem is dark brown and resistant to insect attack due to:
$(a)$ secretion of secondary metabolites and their deposition in the lumen of vessels.
$(b)$ deposition of organic compounds like tannins and resins in the central layers of stem.
$(c)$ deposition of suberin and aromatic substances in the outer layer of stem.
$(d)$ deposition of tannins,gum,resin and aromatic substances in the peripheral layers of stem.
$(e)$ presence of parenchyma cells,functionally active xylem elements and essential oils.
Choose the correct answer from the options given below:

Vascular tissues containing a large number of vessels and fibers are .........

Common bottle cork is a product of ............ .