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<span>The appropriate answer is c. sonar. Oceanographers use sonar to determine the ocean depth. A sonar signal is sent from the ship. Oceanographers record the time taken for the signal to leave the ship and for it to return. Knowing the speed of sound in water, they are able to calculate the depth of the water. This method is also used to generate bathymetric images of the ocean floor. </span>
Because our bodies work to fight off unknown substances like bacteria
