Each annual ring consists of two bands of .........

$I.$ 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.

The waxy substance associated with the cell walls of cork cells that makes them impervious to water is:

An example of monocots showing secondary growth in stems is

When secondary growth in thickness is initiated in a dicot root,which of the following happens first?

What are the balloon-like structures known as tyloses?