Fire pump and bell: what they have in common

1. Step 1. Fire pump — has part — Piston pump. A fire pump is a piston pump.
2. Step 2. Piston pump — is part of — Diving suit. Air was pumped from the surface.
3. Step 3. Diving suit — evolved from — Diving bell. Individual equipment.
4. Step 4. Diving bell — has part — Bell. A body open at the bottom.

Open Evothings