TF阅读真题第833篇The Radiocarbon Dating of Prehistoric American Sites

TF阅读真题第844篇Climate Change and Species Distribution

TF阅读真题第805篇Concealing Coloration

TF阅读真题第817篇The Runaway Greenhouse Effect on Venus

The Birth of the Solar System                                     &nb...

The Greek City-States: Sparta and Athens Of the hundreds of city-states that evolved during the Archaic Age, (800- 479 B.C.), Sparta and Athens stand out for their vividly contras...

TF阅读真题第818篇Easter Island statues

The Origin of Mars's Moons     Mars has two tiny moons, Phobos and Deimos. The orbits of both these satellites are nearly circular and close to the planet: Phobos orbits...

Why Did Agriculture Arise   Sometime around 10,000 years ago, some hunter-gatherers took up agriculture. Though the advantages may seem obvious, there are also disadvantages: ...

Agricultural Origins   It is tempting to think that people started domesticating plants and animals because hunting and gathering was laborious and then someone had the brilli...