The correct answer should be the third one you listed. The "current drag" then is a device that is used in order to measure the sub-surface currents. This device and the measurements it provides are extremely important for the field of oceanography which studies the aspects of the oceans both the physical and the biological ones.
Women's work in WW1. During WWI (1914-1918), large numbers of women were recruited into jobs vacated by men who had gone to fight in the war. New jobs were also created as part of the war effort, for example in munitions factories.
Early farmers who cultivated crops and domesticated animals
"The Southern states have been conquered and should be punished for their actions." is the correct answer.
