An annual ring is formed by
Two consecutive rings of spring wood
Two alternate rings of spring wood and autumn wood
Two consecutive rings of autumn wood
Two alternate rings of sapwood and heartwood
The youngest layer of secondary xylem in the wood of dicot plant is located
Identify $X$ and $Y$ in figure
$X-Y$
Periderm is produced from
Desert grasses often roll their leaves due to presence of
The vascular cambium in dicots is