Indigo   题目： Indigo is a blue dye produced from plants of the genus group Indigofera, grown in tropical and subtropical climates, and it has been highly valued since ancie...

Currency and the Emergence of china's Market Economy 题目：     China's Song dynasty (960-1279 c.E.), building on developments of the earlier Tang dynasty(618-907 c.E...

Horns in Beetle Competition       Intraspecific competition-that is, competition between members of the same species for limited resources-can be a complex phenome...

  The Phenomenon of Hypnosis   题目：   Hypnosis is a process in which the person being hypnotized (the volunteer) demonstrates willingness to adopt suggestions by...

The Search for the Origins of Writing     Who invented the first writing? Like many questions of its type in archaeology, this one is not easily answered. Some might arg...

Lighting in Museums       The practice of reducing light exposure in museums was prompted by the publication, in 1978， of Garry Thomson's book, The Museum Environ...

The Collapse of Copán 题目：   The ancient Mayan kingdom of Copan, in what is now western Honduras, flourished for many years in the first millennium but declined sharpl...

  Where Did the Carbon Go?     Over the last several hundred thousand years, atmospheric carbon dioxide (CO2) levels decreased when Earth's glacial ice sheets were ...

Animal Migration Patterns in the Serengeti   The Serengeti, a region in northern Tanzania, is the site of the largest mammal migration on Earth. Herds of wildebeest, zebras...

Transportation and Urban Development in Los Angeles   题目：   In the early twentieth century, the key urban problem in the United States was congestion. Streetcars (pu...