The five regions of the United States are the Northeast,Southeast<span>, </span>Midwest<span>, West and the </span>Southwest<span>.</span>
The type of sediment that is made up mainly of the shells of diatoms and radiolarians are called the siliceous ooze<span>. Siliceous ooze is a siliceous pelagic sediment that covers large areas of the deep ocean floor. Calcareous ooze, siliceous ooze is formed from the tests of microorganisms; in the case of siliceous ooze, the organisms come in two varieties, diatoms and radiolarians. </span>
The Ancient Maya<span>. </span>Mayan<span> civilization lasted for more than 2,000 years, but the period from about 300 A.D. to 900 A.D., known as the Classic Period, was its heyday. During that time, the </span>Maya<span> developed a complex understanding of astronomy.</span>
