Engine: Expired / General Subjects

1. A The air provides an oxygen source for the aerobic bacteria required for metabolism, and it helps promote settling in the aeration chamber.
2. B The air provides an oxygen source for the anaerobic bacteria required for metabolism, and it helps promote settling in the aeration chamber.
3. C The air provides an oxygen source for the anaerobic bacteria required for metabolism, and it helps prevent settling in the aeration chamber.
4. D The air provides an oxygen source for the aerobic bacteria required for metabolism, and it helps prevent settling in the aeration chamber.

Tip: press A-D to answer