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National Geographic Education brings geography, social studies and science to life. Using real-world examples and National Geographic's rich media, educators, families, and students learn about the world and the people in it.

Explore the updated online encyclopedia from Encyclopaedia Britannica with hundreds of thousands of articles, biographies, videos, images, and web sites.

Geography4Kids.com! The web site that teaches physical geography and earth science basics to everyone!

Definition of word from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games.

YourDictionary is a free online dictionary that offers definition search from Webster's dictionary for word meanings and thesaurus. Use this dictionary search as a crossword or scrabble dictionary. Also find legal dictionary, technical words, glossar...

Dictionary.com - the largest and most trusted free online dictionary. Instantly look up accurate and extensive definitions and word meanings, and hear audio pronunciations.

Online Dictionary - Multiple dictionaries including: English dictionary, medical dictionary, legal dictionary, financial dictionary, computer dictionary, thesaurus, dictionary of acronyms and abbreviations, dictionary of idioms, thesaurus, Columbia e...

Hydrosphere Research Bioassay Laboratory provides aquatic toxicity testing to comply with NPDES permits through whole effluent toxicity testing, acute and chronic testing, water studies and evaluation services.

The Exploratorium isn