Thigmotropism is the response of the plant to

Plant hormones are usually:

Leaves fall off from branches in winter due to

Match the following:

Column $I$	Column $II$
$a.$ Auxin	$(i)$ Root hair formation
$b.$ Cytokinin	$(ii)$ Seed development
$c.$ Ethylene	$(iii)$ Xylem differentiation
$d.$ $ABA$	$(iv)$ Nutrient mobilisation

Phytohormones responsible for cell division in callus are . . . . . . and . . . . . . .

Pick out the correct statements.
$I.$ Cytokinins especially help in delaying senescence.
$II.$ Auxins are involved in regulating apical dominance.
$III.$ Ethylene is especially useful in enhancing seed germination.
$IV.$ Gibberellins are responsible for immature falling of leaves.