The arrangement of secondary xylem and secondary phloem is respectively:

Physiologically,the active part of the wood is ..........

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:

In old dicot stems,a major part of the wood is filled up with tannins,resins,gums,etc. This part of the wood is called:

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

Which of the following represents the correct sequence of layers from the center towards the periphery in a dicot stem?