Engine: Engineering Safety

1. A educating air through "D" and mixing it with water in chamber "E"
2. B educting mechanical foam through "D" and mixing it with water and air in chamber "E"
3. C educting chemical foam through "D" and mixing it with water in chamber "E"
4. D educting air through "C", mechanical foam through "D", and mixing them with water in chamber "E"

Tip: press A-D to answer