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ChemistryThe Periodic Table of Elements I
The modern periodic table is based on Dmitri Mendeleev’s 1896 observations that chemical elements can...
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Scientists and ResearchLouis Tompkins Wright
In the first two decades of the 20th century, job opportunities for African American physicians...
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Earth ScienceThe Phosphorus Cycle
All living organisms need phosphorous to survive and grow. This module describes forms that phosphorous...
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