What was one of the first instruments used to study the ocean?

Sounding weight

Explanation:

Used by Sir James Clark Ross

Sounding weight

The first instrument used for deep-sea investigation was the sounding weight, used by British explorer Sir James Clark Ross. With this instrument, he reached a depth of 3,700 m (12,139 ft) in 1840. The Challenger expedition used similar instruments called Baillie sounding machines to extract samples from the sea bed.

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the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.