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The ship was equipped with air guns ( for seismic reflection soundings deep into the Earth 's mantle ) , magnetometer , gravimeter , 3.5 - kHz and 12-kHz sonar transducers , and precision depth recorders .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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