Some dolphin species face the threat of extinction, often directly as a result of human behavior. The Yangtze River Dolphin is an example of a dolphin species which may have recently become extinct.

Add up opposing sides of a dice cue and you'll always get seven.

Mark Twain was born on a day in 1835 when Halley's Comet came into view. When he died in 1910, Halley's Comet was in view again.

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