Periderm is produced from

Diffuse-porous wood is a characteristic feature of plants growing in .........

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $A$: Late wood has fewer xylary elements with narrow vessels.
Reason $R$: Cambium is less active in winters.
In the light of the above statements,choose the correct answer from the options given below:

In heartwood,the conduction of sap is mostly blocked due to the presence of:

In roots and stems,secondary growth takes place after the formation of

The age of a tree can be estimated by: