Tax returns and supporting documentation. The IRS has three years to challenge your tax returns, so you must keep them at least that long. It's wise to keep tax returns for at least six years, because if the IRS suspects you may have under-reported income, it has six years to challenge returns.
How is the Earth's crust related to tectonic movement? The convection currents in tectonic plates occur in the geosphere. The radioactive decay of elements is responsible for the heat deep within the earth, and this results in the creation of magma. Magma is a type of material that can be semi-fluid or completely fluid.
Surface ocean currents are primarily driven by winds. Deep ocean currents, on the other hand, are mainly a result of density differences. The thermohaline circulation, often referred to as the ocean's conveyor belt, links major surface and deep water currents in the Atlantic, Indian, Pacific, and Southern Oceans.urface ocean currents are primarily driven by winds. Deep ocean currents, on the other hand, are mainly a result of density differences. The thermohaline circulation, often referred to as the ocean's conveyor belt, links major surface and deep water currents in the Atlantic, Indian, Pacific, and Southern Oceans.