[Campbell Biology P.897] Which statement accurately describes the effect of auxin concentrat... | Practice Question
Which statement accurately describes the effect of auxin concentration on cell elongation?
A: Auxin stimulates growth at all concentrations, with higher concentrations leading to faster growth.
B: Auxin only inhibits cell elongation, regardless of concentration.
C: Auxin stimulates growth only over a certain concentration range (10^-8 to 10^-4 M), inhibiting it at higher concentrations.
D: Auxin's effect on cell elongation is unrelated to its concentration.
Explanation
The text explicitly states: 'Auxin stimulates growth only over a certain concentration range, from about 10^-8 to 10^-4 M. At higher concentrations, auxin may inhibit cell elongation by inducing production of ethylene...'