A few years ago, the labels from one class section's experimental treatments plants fell off in the greenhouse and got swept away! One group was the only group in the section to test the effects of...

A few years ago, the labels from one class section's experimental treatments plants fell off in the greenhouse and got swept away! One group was the only group in the section to test the effects of indole acetic acid (IAA) on bean plants. Other groups applied GA to their bean plants. The IAA group applied lanolin paste to one side of their bean stems. What should they for in order to identify their experimental plants from other groups?