¿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.

Presents general information about Christmas, including the origins of the holiday and other fall and winter holidays and their traditions, provides instructions for seasonal craft projects, and describes celebrations in different lands.

Con un sentido de humor este libro ilustrado para niños y jóvenes cuenta la historia sobre la vida de los soldados romanos en el tiempo del emperador Adriano.

Defender la Luz Mientras el mundo occidental caía en la oscuridad, ella se atrevió a defender la luz. Hipatia de Alejandría, nacida en el año 355, tras el reinado de Constantino, vivió en un Imperio Romano que se derrumbaba, un mundo en el que la obediencia a las autoridades religiosas triunfaba sobre la ciencia, en el que la razón y la lógica amenazaban el nuevo orden mundial. Era un mundo al borde de la Edad Media, un mundo que decidía la cuestión de la ciencia versus la religión, la libertad versus la ortodoxia, la tolerancia versus el odio. Durante más de 40 años, Hipatia se...

Recounts the life of the Puerto Rican baseball star from his childhood poverty to his career with the Pittsburgh Pirates, and discusses his humanitarian efforts, his untimely death, and his contributions to the sport.