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...

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: ...

  Archaeoptertx and Flight 题目： It is not known whether Archaeopteryx, the earliest birdlike creature for which fossils have been found, could fly-but it probably did, at ...

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...

Language and Migration 题目： The study of language can offer important clues about the historic migration of people around the world. Most historians would place the emergence o...

Degradation and Erosion of Soil Land without soil can support only very small primitive plants such as lichens and mosses that can cling onto a rock surface. The rest of the worl...

Creativity   A basic question about creativity is, what factors produce it? Several contrasting answers have been proposed. Cognitive psychologists, for example, have tended t...

How Did Life Begin For life to begin, it needed the right sorts of molecules, some sort of energy(such as that created by lightning), and the right environment-perhaps the 'warm l...

Building Materials in the Nineteenth Century       For most of the nineteenth century, European architects built in historical revival styles (styles that imitate ...