Final answer:
Spores of Bacillus atrophaeus are used to monitor sterilizers like autoclaves.
Step-by-step explanation:
Spores of Bacillus atrophaeus are used to monitor the effectiveness of sterilizers such as autoclaves. Autoclaves rely on moist-heat sterilization to raise temperatures above the boiling point of water and destroy microorganisms, including endospores. Biological spore indicators like Bacillus atrophaeus spores are used to test the effectiveness of sterilization protocols.