Plastic bottle and davy lamp: what they have in common

1. Step 1. Plastic bottle — evolved from — Glass bottle. A replacement for glass.
2. Step 2. Glass bottle — includes — Soda siphon. A soda siphon is a strong bottle charged with carbon dioxide.
3. Step 3. Soda siphon — has part — Valve. A valve.
4. Step 4. Valve — is part of — Carbide lamp. It regulates the water supply.
5. Step 5. Carbide lamp — evolved from — Davy lamp. Miners’ lamps.

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