¿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.

Although Earth is mostly made up of igneous and metamorphic rock, sedimentary rock covers about 75 percent of Earth's land surface. This means it's the most visible kind of rock on Earth. Sedimentary rocks form when sediment accumulates and compacts. Your readers will learn how sedimentary rocks form, the different types of sedimentary rocks, and how people use sedimentary rocks. Fun fact boxes provide readers with additional information. A helpful diagram illustrates how sedimentary rocks form.

When rocks change because of environmental conditions, the new rocks are called metamorphic rocks. A rock's chemical or physical makeup may change because of conditions such as temperature, stress, or pressure. Your readers will learn fascinating facts including where metamorphic rocks are most commonly found, the different types of metamorphism, and how metamorphic rocks are identified. Full-color photographs depict these rocks in nature. A helpful graphic organizer shows how these fascinating rocks form.

Esta obra reúne textos escritos por Andrés Lira sobre el exilio español y los maestros de ese exilio, como: José Medina Echavarría, José Miranda, Ramón Iglesia, Juan Antonio Ortega y Medina, Eugenio Ímaz y José Gaos, quienes han formado parte tanto de la Universidad Nacional Autónoma de México como de El Colegio de México.

Luis Suárez is known as one of the best soccer players in the world. He has won trophies, championships, league titles, and can shoot goals with either foot. As gifted a player as he is, Suárez is also known to be a controversial figure in the sports world. This book draws young soccer fans in with bright photographs of the exciting sport in action. Cool fact boxes are also sprinkled throughout the book to support the text. Readers will get an inside look at Suárez's achievements, his struggles, and his amazing athleticism.

"Simple text and photos present the seasonal weather cycle and activities to do in each season"--Provided by publisher.

Las miles de aventuras de Leo San Juan. ¡Basado en la película La leyenda del Charro Negro! Leo y Nando San Juan están felices de haber vencido al Chupacabras. Tras despedirse de los insurgentes, y una vez más en el camino hacia Puebla, una nueva misión les impide llegar con su abuela: el Charro Negro se ha llevado el alma de una niña y, para recuperarla, Leo debe cruzar al inframundo y completar una serie de pruebas. Aun con la ayuda de todos sus amigos, ésta será la misión más difícil que el chico haya tenido que resolver hasta ahora; más allá de enfrentar a las criaturas...