Usually, the monocotyledons do not increase their girth, because ____.

(a)

They possess actively dividing cambium

(b)

They do not possess actively dividing cambium

(c)

Ceases activity of cambium

(d)

All are correct

The common bottle cork is a product of______.

(a)

Phellem

(b)

Phellogen

(c)

Xylem

(d)

Vascular cambium

What is the fate of primary xylem in a dicot stem showing extensive secondary growth?

(a)

It is retained in the centre of the axis

(b)

It gets crushed

(c)

May or may not get crushed

(d)

It gets surrounded by primary phloem

In which season the vessels of angiosperms are larger in size, why?

A transverse section of the trunk of a tree shows concentric rings which are known as growth rings. How are these rings formed? What are the significance of these rings?