Hadal zone definitions

Hadal zone

1) Extreme point of Earth
Found on https://www.crosswordclues.com/clue/hadal-zone

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hadal zone

(from the article `marine ecosystem`) ...continental slope and rise. The abyssal zone (between 4,000 and 6,000 metres) represents a substantial portion of the oceans. The deepest region ...
Found on http://www.britannica.com/eb/a-z/h/2

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