Growth rings are absent or not sharply demarcated in the trees of

In old trees,the greater part of secondary xylem is dark brown due to the

Define the following terms:
$(i)$ Early wood
$(ii)$ Late wood

$A$ : The oldest layer of sapwood lies just outside the vascular cambium.
$R$ : Sapwood contains actively conducting vessels and occupies the central part of the stem.

In cambium,the amount of secondary xylem produced is more than secondary phloem because..........

In dicot stems,the cork cambium (phellogen) first develops from the: