Other names of secondary cortex,cork cambium and cork are

Describe the contribution of cork cambium in secondary growth.

The function of the $phellogen$ (cork cambium) is to produce $........$.

Early wood is formed in dicot plants during

Complete the following analogy-type questions:
$(i)$ Cells of cambium between vascular bundles : Intrafascicular cambium :: Cells of medullary rays : .....
$(ii)$ Cambium cells dividing towards the pith : Secondary xylem :: Cambium cells dividing towards the periphery : .......

$I.$ 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.