Final answer:
Yeast is an example of a saprophyte, an organism that feeds on dead organic matter, typically using enzymes to break it down and absorb nutrients.
Step-by-step explanation:
Among the options provided, yeast is an example of a saprophyte. A saprophyte is an organism that feeds on dead organic matter, and yeast can act as a decomposer in this capacity. Most saprophytes are fungi or bacteria that use enzymes to break down dead material and absorb nutrients; this includes the decomposing action on wood, where fungi play an exclusive role. It's worth noting that the term 'saprophyte' is somewhat outdated and is more accurately replaced by 'saprotroph' for organisms like fungi that feed externally on decayed organic material.