Elongation of internodes is inhibited by

You are given a tissue with its potential for differentiation in an artificial culture. Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots?

$I.$ Kinetin is a degradative substance from $DNA$.
$II.$ $ABA$ is present in all plants including lower plants.
$III.$ Low ratio of cytokinin to auxin favours root formation only.
$IV.$ $ABA$ is synthesized catabolically through glycolysis pathway.
Choose the correct combination of options.

Chromosome number can be doubled by using which of the following?

Ratio of . . . . . . and . . . . . . plant hormones and their interactions control the morphogenic differentiation.

Statement-$I$: Spraying sugarcane crop with $\text{IAA}$ can increase the yield by $20$ tonnes per acre.
Statement-$II$: Cotton and coriander represent developmental heterophylly.