What is the precursor of $IAA$?

The pineapple,which under natural conditions is difficult to blossom,has been made to produce fruits throughout the year by the application of:

The bending of a shoot towards light is known as....

After a series of experiments,it was concluded that the ...$A$... of coleoptile was the site of transmittable influence that caused the ...$B$... of the entire coleoptile. Complete the given statement with the correct combination of options given in the codes below.

Mowing a grass lawn facilitates better maintenance primarily owing to:

The direction of the transport of auxins is