¿Por qué hibernan los animales? (Why Animals Hibernate)

The rock cycle has been taking place for millions of years. However, geologists have only known about this phenomenon for about 300 years. Young terrestrial explorers are introduced to different types of rocks, where in the cycle these rocks fit, and where in Earth's layers each step takes place. Fact boxes provide readers with fun additional information. A diagram helps readers make sense of the new information they're learning.

Diamonds and salt are both minerals, but diamonds are more rare than salt. Curious readers will learn what physical and chemical conditions must be present for minerals to form. They'll discover how minerals are identified and how they are used in daily life. Informative and interesting text presents readers with this science content in a fun way. A graphic organizer shows how different minerals are identified and fact boxes provide readers with exciting supplementary information.

The greatest thinkers of humanity at your fingertips, in minutes! If you thought you would never be able to understand the essential classic authors, you were wrong! With our "Selected Summaries" collection, you will understand the main ideas of the most important thinkers in a very short time and with little effort. The present volume covers the central axes of this discipline. Among them, the reader will find an analysis of the following: A Journey Through The Economy Of Our Time, History Of The Economy, The Culture Of Satisfaction, A Better Society, among others.

Este es un libro para nios, sobre un oso que...¡sólo comía chocolate! No comía vegetales ni ninguna fruta. Sólo comía chocolate. El oso no comía arroz. Tampoco comía cereales. Nunca nadie podría llegar a verlo comiendo yogur o algo, que todos podríamos llamar...saludable. Sólo le gustaba el chocolate. Por supuesto, mucha cantidad de algo "bueno" a menudo es malo, y llevar una dieta no balanceada no ayudaría al oso a crecer y ser fuerte y grande. Mucho amor por el chocolate inclusive podría hacer que el oso se metiera en problemas. Cuando se le termina el chocolate y a sus amigos...

El joven Temujin se ha convertido en Gengis Khan, el victorioso comandante que conseguirá unir a las tribus más belicosas de las estepas. Su intención es forjar una nueva nación en las salvajes llanuras y montañas de Mongolia, un nacimiento sangriento que pondrá a un continente de rodillas. Durante miles de años, las tribus han sido mantenidas a raya por las fortalezas del imperio de los Chin, una tierra de enorme riqueza e ingentes ejércitos imbatibles. A cambio, los guerreros de Gengis sólo poseen el arco, el caballo y una disciplina de hierro nacida de una tierra de hielo, hambre...

Your lungs make sure that you use air wisely. Learn how the air passes from the lungs to the bloodstream in this story about your amazing body.