Question

On average, the illuminated zone in oceans is to a depth of ________, but in some oceans may be as deep as ________.
A) 20 m (66 ft); 30 m (100 ft)
B) 100 m (330 ft); 500 m (1,640 ft)
C) 60 m (200 ft); 300 m (1,000 ft)
D) 30 m (100 ft); 900 m (3,000 ft)

Answer

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