text: F-box protein TIR1 is a receptor for these compounds. These compounds activate proton pumps which in turn activate expansins.
full_question: F-box protein TIR1 is a receptor for these compounds. These compounds activate proton pumps which in turn activate expansins. These compounds move via a namesake "polar transport" whose direction is controlled by PIN proteins. These compounds cause elongation per the acid growth hypothesis. Two of these compounds were mixed to make Agent Orange. An experiment involving growth of a coleoptile of monocots on agar led to the discovery of these compounds and their role in phototropism. The most common form of these compounds in nature is indole-3-acetic acid. For 10 points, name this plant hormone which promotes growth.
first_sentence: F-box protein TIR1 is a receptor for these compounds. These compounds activate proton pumps which in turn activate expansins.
raw_answer: auxins [prompt on indole-3-acetic acid or IAA until "Agent" is read] 