Annual ring appears due to

(1) Radial xylem

(2) Radial phloem

(3) Centric wood

(4) Alternate concentric rings

The region of secondary xylem which comprise dead element with highly lignified walls is called

The peripheral region of secondary xylem lighter in colour is

Cork cambium is also called

Phellogen, phellem and phelloderm are collectively known as

Bark that is formed early in season is called __________ bark.

1. Hard

2. Soft

3. Turbid

4. Lenticels

Bark formed towards the end of the season is called ________ bark.

The exchange of gases between the outer atmosphere and internal tissue of stem is through ___________.

In dicot root the vascular cambium is completely _________ in origin.

Which one yields fibres?
1. Coconut
2. Oak
3. Teak
4. Sisso