$A$ clinostat is an instrument used in experiments related to:

Elongation of internodes is inhibited by

During experimentation, why is it difficult to attribute any observed effect to a single hormone?

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

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.

Polyploidy can be induced by the application of