Which of the following is a plant hormone?

Desert can be converted into greenland by

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

Study the following statements.
$I.$ "$X$" hormone promotes root growth and root hair formation, thus helping the plants to increase their absorption surface.
$II.$ "$Y$" hormone induces flowering in mango and also promotes rapid internode/petiole elongation in deep-water plants, hence helping leaves or upper parts of the shoot remain above water.
$III.$ "$Z$" hormone inhibits seed germination, increases the tolerance of plants to various stresses, and plays an important role in seed development, maturation, and dormancy.
Identify the correct names of hormones marked as $X$, $Y$, and $Z$.

Identify the plant growth promoters and plant growth inhibitors.

What is the role of light in plants?