$2, 4-D$ is an effective:

$A$ well-known naturally occurring auxin is, or a natural growth regulator (hormone) is:

If the seedlings are grown in darkness,what is their physical appearance compared to those grown in light?

In botanical gardens and tea gardens,gardeners trim the plants regularly so that they remain bushy. Does this practice have any scientific explanation?

$A$ practical application of an auxin is to induce

$I.$ Cell elongation
$II.$ Cell division
$III.$ Cell differentiation
Among the above mentioned,what is/are the function$(s)$ of auxin?