The vascular cambium normally gives rise to

Knots in stems are formed due to

Identify the correct statements:
$A$. Lenticels are the lens-shaped openings permitting the exchange of gases.
$B$. Bark formed early in the season is called hard bark.
$C$. Bark is a technical term that refers to all tissues exterior to vascular cambium.
$D$. Bark refers to periderm and secondary phloem.
$E$. Phellogen is single-layered in thickness.
Choose the correct answer from the options given below:

Identify the incorrect statement regarding heartwood.

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

Which tissue gives rise to secondary growth?