Final answer:
The correct answer is C. Scavenger.
Step-by-step explanation:
The correct answer is C. Scavenger. A scavenger is an organism that feeds on dead or decaying organic matter. In the context of the question, a scavenger is used primarily to vent waste gases. For example, in nature, vultures are scavengers that feed on the carcasses of dead animals, helping to clean up the environment.