How many of the following auxins are obtained from plants?
IAA, IBA, NAA, 2,4-D
Auxins like indole-3-acetic acid (IAA) and indole butyric acid (IBA) occur naturally and have been isolated from plants. NAA (naphthalene acetic acid) and 2, 4-D (2, 4-dichlorophenoxyacetic) are synthetic auxins.