Stomata are the component of

The characteristic feature of a bicollateral vascular bundle is ............ .

$A$ vascular bundle in which the phloem is found on both sides of the xylem is called .....

Water secreting glands or tissues are known as

Which xylem element is living?

Select correct features w.r.t. trichomes in the shoot system:
$(a)$ Usually unicellular
$(b)$ Branched or unbranched
$(c)$ May be secretory
$(d)$ Soft or stiff
$(e)$ Helps against transpiration