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The Mississippi's Curious Origins

A mountain range once separated the continental interior of the U.S. from the Gulf of Mexico. Some clever geologic sleuthing has revealed how that barrier was breached, allowing the river to reach the Gulf

By Roy B. Van Arsdale and Randel T. Cox

The Power of Riboswitches

Discovering relics from a lost world run by RNA molecules may lead to modern tools for fighting disease

By Jeffrey E. Barrick and Ronald R. Breaker

What Is a Planet?

The controversial new official definition of "planet," which banished Pluto, has its flaws but by and large captures essential scientific principles

By Steven Soter


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January 2007

Think Outside the Gift Box