Suberin is a ..........

The most primitive type of stele is

Select the correct statements.
$I.$ Epidermal cells have a small amount of cytoplasm and a large vacuole.
$II.$ $A$ waxy layer,the cuticle,is absent in roots.
$III.$ Root hairs are unicellular,while stem hairs/trichomes are multicellular.
$IV.$ Trichomes are branched/unbranched,soft/stiff,and secretory or transpiration-preventive.
$V.$ Guard cells are dumb-bell-shaped in monocots (e.g.,grass) and bean-shaped in dicots.

When in a stele the xylem is surrounded by phloem,the condition is called

All the tissues on the inner side of the endodermis together constitute the

$A$ vascular bundle in which a group of xylem and a group of phloem are on the same radius with xylem near the pith and phloem near the cortex and both are not separated by the cambium,is called: