The answer is B. Hydrosphere
An ocean current is a continuous movement of water in the ocean in some direction - this means that the water flows at a similar speed and direction despite the fact that it's not the same water - i.e. there is a water exchange in the current. The currents are caused by such factors as temperature and salinity of water.
Answer: In some parts of the world, windblown dust and silt blanket the land. This layer of fine, mineral-rich material is called loess. Loess is mostly created by wind, but can also be formed by glaciers. When glaciers grind rocks to a fine powder, loess can form.
Lead was not vital for economic success.
