From where was auxin first isolated?

Step-by-step solution

Auxins (from Greek ‘auxein’: to grow) was first isolated from human urine .The term ‘auxin’ is applied to the indole-3-acetic acid (IAA), and to other natural and synthetic compounds having certain growth regulating properties.They are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action