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...

    The Collision Model of the Moon's Formation       The collection and analysis of rocks brought back from the Moon during the Apollo spaceflight prog...

A Cat's Sense of Smell     题目： Cats have sensitive noses that they use for a variety of purposes, including finding mates and identifying the territory of other cats...

  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...

Is Panspermia Possible 题目：   In 1996,NASA scientists claimed that Allan Hills 84001 (abbreviated ALH 84001),a meteorite containing materials ejected from Mars 15 million ...

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...

Early Photography in the United States     When photography first appeared in 1839 with the introduction of the daguerreotype, it was celebrated for revealing the truth ...

TF阅读真题第941篇Megapode Approaches to Incubation Megapode Approaches to Incubation 题目：     The megapodes are a family of birds with unusually large legs. Alone am...

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