Science & Social Studies
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Biology
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In 1665, Robert Hooke coined the term cell to describe the structures he could see in cork with some of the first microscopes. Since then, technology has given us an increasingly complex view of the basic unit of life. interactive explore
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Scientific Method Web Page
Observations Before you conduct an experiment, you always make observations.
Interactive Constitution
Use the search box to the right to search for keywords in the text of the Constitution and the in-depth explanations we've linked to it.