In plasma, the half-life of

 A. False It is the time it takes for the initial concentration to fall by half.

B. False It is much shorter (about five minutes); this allows more precise and continuous regulation of the blood glucose level.

C. True It is much longer since moment to moment regulation of its level is less critical.

D. True It is more highly protein-bound which appears to prolong its life.

E. True Acetylcholine is broken down almost immediately by cholinesterase.