Multiple choice Which of the following chemicals is/are used in seed viability testing? Orchine and water Uric acid and gibberellic acid Triphenyl tetrazolium chloride Colchicine and water Reveal answer Fill a bubble to check yourself C Correct answer Explanation Triphenyl tetrazolium chloride, TTC, or simply tetrazolium chloride is a redox indicator commonly used in biochemical experiments especially to indicate cellular respiration.