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.
Illustration of major ocean currents throughout the globe. Ocean currents act as conveyer belts of warm and cold water, sending heat toward the polar regions and helping tropical areas cool off. The worldâs ocean is crucial to heating the planet. While land areas and the atmosphere absorb some sunlight, the majority of the sunâs radiation is absorbed by the ocean. Particularly in the tropical waters around the equator, the ocean acts a as massive, heat-retaining solar panel.