Which of the following is a widely used second messenger in signal transduction pathways? Naim 04:57 AP Biology Practice Questions Which of the following is a widely used second messenger in signal transduction pathways? A) calcium ions B) cyclic AMP C) inositol trisphosphate D) A and B only E) A, B, and C Answer: E Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+