The correct answers are 3 and 4. The Panama Canal, built in 1914, has managed to reduce maritime communication in time and distance, boosting commercial and economic exchange by providing a short and relatively cheap transit route between the two oceans, decisively influencing global trade patterns.
Before its construction, the ways to move people or goods between New York and San Francisco were traveling overland across North America, as at that time the airplanes had not been developed to cover such long distances, or by sailing for more than a month all the way around South America to the Beagle Channel.
<span>Hydraulic mining, or hydraulicking, is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment. In the placer mining of gold or tin, the resulting water-sediment slurry is directed through sluice boxes to remove the gold. It is also used in mining kaolin and coal.</span>
