Auxin Triggers the Acidification of Cell Walls That Results in Rapid

Multiple Choice

Auxin triggers the acidification of cell walls that results in rapid growth, but also stimulates sustained, long-term cell elongation. What best explains how auxin brings about this dual growth response?

A) Auxin binds to different receptors in different cells.
B) Different concentrations of auxin have different effects.
C) Auxin causes second messengers to activate both proton pumps and certain genes.
D) The dual effects are due to two different auxins.
E) Other antagonistic hormones modify auxin's effects.