Cartridge and lead–acid battery: what they have in common

1. Step 1. Cartridge — is part of — Machine gun. Cartridges in a belt.
2. Step 2. Machine gun — is part of — Tank. The Mark I’s machine guns.
3. Step 3. Tank — has part — Periscope. Observation devices.
4. Step 4. Periscope — is part of — Submarine. A periscope.
5. Step 5. Submarine — has part — Lead–acid battery. Underwater, electric motors run on batteries.

Open Evothings