Physics
Magnetic keepers are used to protect magnets from :

Earth's magnetic field
Self-demagnetization
Demagnetization due to heating
Effect of other magnets

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Physics
Thermohaline circulation is mainly due to

Warmer, less dense water sinking in the ocean and cold water replacing it
Winds causing circulation of ocean water
Warm water being added to the ocean due to industial waste
Cold, dense ocean water sinking and warmer water replacing it

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