The xylem which is functional in a dicot tree is:

The secondary growth in the stem of $Cycas$ is brought about by:

Assertion: In the stem,the pericycle takes an active part in secondary growth.
Reason: In dicots,the pericycle has the capacity to produce lateral roots.

In a plant organ which is covered by periderm and in which the stomata are absent,some gaseous exchange still takes place through

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:

Which of the following is true regarding diffuse-porous and ring-porous wood?