Complementary cells are associated with

A transverse section of the trunk of a tree shows concentric rings which are known as growth rings. How are these rings formed ? What is the significance of these rings ?

In which of the following secondary growth takes place

Explain the process of secondary growth in stems of woody angiosperm with help of schematic diagrams. What is the significance?

In the primary tissues of the stem, the cambium separating xylem and phloem is called

Give explantion about heartwood and sap wood.