Identify the incorrect pair$(s)$ from the following:

Which of the following sets is not a natural plant growth regulator?

Which of the following is not an extrinsic factor affecting plant growth?

Movement of a plant part in response to touch is known as:

The movement of leaves in $Mimosa$ $pudica$ is due to:

$I.$ 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.