Why is a system’s work output limited? a. entropy decreases with each stage of a system, causing a decrease in available entropy to carry out each stage. b. systems tend to become less randomized over time, which causes spontaneous processes to no longer occur. c. energy is destroyed in each stage, causing the amount of available energy to decrease with each stage. d. energy is lost as heat in each stage, causing the amount of energy available to decrease with each stage.