Annual rings and growth rings are formed due to the fluctuation in the activity of .......... .

The cork is impervious to water due to

Commercial cork is obtained from

Read the different components from $(i)$ to $(iv)$ in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem.
$(i)$ Secondary cortex $(ii)$ Wood $(iii)$ Secondary phloem $(iv)$ Phellem
The correct order is:

Which of the following statements is incorrect regarding sapwood?

As a tree grows older,which part increases rapidly in thickness?