Which of the following hormones is synthetic?

In unisexual plants,sex can be changed by the application of

Identify the functions of auxin and choose the correct option.
$I.$ Initiate rooting in stem cuttings
$II.$ Promote flowering in pineapples
$III.$ Controls xylem differentiation

$A$: $2, 4-D$ is widely used by farmers in agricultural and horticultural practices.
$R$: Flowering in most plants can be initiated by using high concentration of Auxin.

To get a carpet-like grass,lawns are mowed regularly. Is there any scientific explanation for this?

Auxin can be bioassayed by