Plants having little or no secondary growth are

Cambium is present in between

$A$: Bark is all the tissues outside the vascular cambium.
$R$: Bark is formed due to the activity of phellogen only.

$I.$ Annual rings are formed as a result of seasonal environmental conditions.
$II.$ Tracheids/vessel elements are larger during periods when water is abundant.
$III.$ Tracheids/vessel elements have thicker walls during periods of water deprivation.
$IV.$ Wood formed in previous years is always darker than newer wood.
Select the combination of correct statements from the options given below.

In dicot stem,the cells of cambium present between the primary xylem and primary phloem is $..........$

The cambium which produces cork is known as