Final answer:
The best metric unit to measure the depth of the Pacific Ocean is meters.
Step-by-step explanation:
The best metric unit of length to measure the depth of the Pacific Ocean would be meters. The Pacific Ocean is a large body of water, and meters are commonly used for measuring long distances. For example, the Mariana Trench, the deepest part of the Pacific Ocean, has a depth of approximately 10,994 meters. Using millimeters would be too small of a unit, and using kilometers would result in large numbers that might be difficult to comprehend when measuring ocean depths.
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