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A glacial valley cross-sectional shape is a U shape whereas a stream valley is usually a V shape. The U shape comes from the scouring action of the alpine glaciers which carries rocks with it which can abrade the walls of the valley and the glacier occupies the whole valley so scours out such a shape whereas the stream cuts down and water washes in from the sides of the valley into the stream or river creating the V shape.
Currents involve movement of ocean water masses, driven either by wind or by differences in temperature, salinity and density. The most important from a human perspective are the wind-driven surface currents that move water in the uppermost layer of the ocean.
Currents affect humans in several primary ways. Currents help shape the climate in the areas where we live, create the right conditions to support abundant ocean life in the areas where we fish, and change weather patterns through periodic events like El Nino/La Nina.
Ocean currents also cause upwelling in many areas like off in the inland parts of North America, where surface currents taking water away from the shore cause nutrient-rich water to well up from the ocean deeps. The abundance of nutrients in these areas forms fertile ground for kelp beds and marine fisheries, which in turn furnish food for humans. Alterations in current patterns like the El Nino/La Nina cycle affect humans as well by causing changes in local weather patterns in the years when they occur.
For larger populations, you need more agriculture. Thefore, the agriculture industry has to work even harder to provide.
The predominant use of oil in the United States is used for transportation.
