$I.$ Auxin,$II.$ Cytokinin,$III.$ $GA$,$IV.$ $ABA$.
Which of the above-mentioned $PGR$ are acidic in nature? Choose the correct option accordingly.

Match the following concerning the activity function and the phytohormone involved.

Column $I$	Column $II$
$(a)$ Fruit ripener	$(i)$ Abscisic acid
$(b)$ Herbicide	$(ii)$ $2,4-D$
$(c)$ Bolting agent	$(iii)$ $GA_{3}$
$(d)$ Stress hormone	$(iv)$ Ethephon

Select the correct option from the following:

Match the following:
Column-$A$ | Column-$B$
$(1)$ Auxin | $(I)$ Ripening and maturity of fruits
$(2)$ Gibberellin | $(II)$ Differentiation of xylem elements
$(3)$ Cytokinin | $(III)$ Prevention of genetic and physiological dwarfism
$(4)$ Ethylene | $(IV)$ Found from tumour tissue of tobacco

The role of ethylene and abscisic acid is both positive and negative. Justify the statement.

Match the following (Column-$I$ with Column-$II$):

Column-$I$	Column-$II$
$a.$ Ethephon	$(i)$ $GA$
$b.$ Terpene	$(ii)$ Ethylene
$c.$ Zeatin	$(iii)$ Natural auxin
$d.$ $IAA$	$(iv)$ Cytokinin

Distinguish between:
$(1)$ Cell enlargement and Cell differentiation
$(2)$ Epigeal germination and Hypogeal germination