A pharmaceutical company is testing two drug delivery methods. Method A uses a targeted electrical impulse to deliver a drug to a single muscle, causing an immediate but very brief effect. Method B releases a drug into the bloodstream, which then circulates throughout the body, causing a gradual but long-lasting change in the body's overall metabolic state. Which of these methods is more analogous to the body's system of glands that secrete chemical messengers? Justify your reasoning by describing at least two key characteristics of that system that are reflected in your chosen method.