yolk sac

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human embryonic development

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Flag of Bhutan

6 Small Kingdoms of the World

Hemp (Cannabis sativa).

9 Mind-Altering Plants

United States Presidential Election of 2012. Mitt Romney. Official portrait of President Barack Obama in the Oval Office, Dec. 6, 2012 after his reelection Nov. 6, 2012. Official portrait Obama

10 Democrats Who Made History

United States elections portal page linking to each election interactive

A History of U.S. Presidential Elections in Maps

Washington, D.C. locator map.

What State Is Washington, D.C. In?

World Data Locator Map: Australia

Is Australia an Island?

Andrew Jackson delivering a speech while on his way to Washington, D.C., for his inauguration in 1829. From Harper's Weekly, 1881.

5 Remarkably Close U.S. Presidential Elections

yolk sac: Media

biology

Images

Amniotic egg.

Amniotic egg.

Encyclopædia Britannica, Inc.

human embryonic development

human embryonic development

Development of the human embryo at 23 days.

Encyclopædia Britannica, Inc.