Agujeros negros (Black Holes)

For many years, people believed there were nine planets that orbited the sun. Now we say there are eight. What happened to the ninth planet, Pluto? What are the different planets like? What exactly makes a planet a planet? These are the many intriguing questions answered with this high-interest book, crafted to be accessible for readers of all levels. Young astronomers will be especially fascinated by the stunning photographs and the "Make the Grade" fact boxes.

Take a trip to New Orleans with a young girl and her family as they attend one of the world's biggest parties: Mardi Gras! Learn all about the history of this fascinating festival as you practice subtraction strategies. This fiction math book combines math and literacy skills, and uses real-life examples of problem solving to teach subject area content. The full-color images, engaging sidebars, practice problems, and math diagrams make learning subtraction strategies relevant and fun. Text features include a table of contents, glossary, and index to increase understanding of math and reading...

Alguien está dando muerte a los Cazadores de Sombras del círculo de Valentine, y esas muertes enemistan de nuevo a los Cazadores de Sombras con los subterráneos. Sólo Simon, ahora convertido en vampiro, podrá evitar el enfrentamiento. Mientras, Clary y Jace descubrirán un misterio que les llevará a fortalecer su relación o... a destruirla para siempre.

Introducción biográfica y crítica. 1. Gabriel Celaya: hombre de un tiempo. 2. Gabriel Celaya: poeta en el tiempo. Noticia Bibliográfica. Bibliografía Selecta. Abreviaturas Utilizadas. Nota Previa. Trayectoria Poética. Antología. Índice de Primeros Versos. Índice de Poemas. Índice de Láminas.

In this Spanish title, learn causes of extinction and what problems extinction causes for animals, wildlife, and humans alike.