What should be added with auxin to hasten cell division in callus?

Shoot differentiation is controlled by which of the following?

Study the following statements:
$I.$ Cytokinins are formed primarily in roots.
$II.$ Auxin and cytokinin are antagonistic in apical dominance.
$III.$ Kinetin (a modified $DNA$ purine) was discovered from herring sperm.
$IV.$ Zeatin is auxin.
$V.$ Zeatin was firstly extracted from herring.
Choose the incorrect one.

Which phytohormone is useful for the formation of interfascicular cambium during the secondary growth of plants?

Which of the following causes delaying of senescence?

Induction of cell division and delay in senescence is done by