Which tissue gives rise to secondary growth?
Apical meristem
Adventitious roots
Germinating seed
Vascular cambium
Commercially important fibres of cotton are
$A$ : Oldest layer of sapwood lies just outside vascular cambium.
$R$ : Sapwood contains actively conducting vessels and occupies central part of stem.
The collective name for cork cambium and phelloderm is
Trunks of some of the aged tree species appear to be composed of several fused trunks. Is it a physiological or anatomical abnormality ? Explain in detail.