Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth,flowering,and rooting. Write a line to explain the meaning of the following terms related to auxins:
$(a)$ Auxin precursors
$(b)$ Antiauxins
$(c)$ Synthetic auxins

(N/A) Auxin precursors: These are substances that serve as the biological starting material for the synthesis of auxins. For example,tryptophan is a well-known precursor for the biosynthesis of indole$-3-$acetic acid $(IAA)$ in plants.
$(b)$ Antiauxins: These are chemical substances that inhibit or antagonize the physiological actions of auxins. Examples include $p$-chlorophenoxyisobutyric acid $(PCIB)$ and $2,3,5$-triiodobenzoic acid $(TIBA)$.
$(c)$ Synthetic auxins: These are artificially synthesized chemical compounds that mimic the physiological properties and effects of natural auxins. Examples include naphthalene acetic acid $(NAA)$ and $2,4$-dichlorophenoxyacetic acid $(2,4-D)$.