In a vertical section of a dorsiventral leaf,the protoxylem in its midrib bundle:

The vertical section of a dorsoventral leaf through the lamina shows three main parts namely,epidermis,$A$,and vascular system. The epidermis,which covers the upper surface is $B$ and the lower surface is covered by $C$ of the leaf. Choose the correct combination of $A$,$B$,and $C$.

Palisade parenchyma is absent in leaves of

The vestigial stomata are present in

$I.$ Sunflower seed
$II.$ $A$ wheat leaf
$III.$ Pea plant
$IV.$ Leaf blade of grass
Bulliform cells are present in which of the above plants?

The location of bulliform cells is $...................$