Un día de trabajo de un biólogo molecular (A Day at Work with a Molecular Biologist)

Tara and her friends go to a street fair. Build early literacy skills, and develop oral and written language skills in emerging Spanish readers with this leveled fiction reader.

En los primeros siete números de la colección te hemos enseñado a diseñar personajes, a escribir historias y desarrollarlas... Ahora es el momento de crearles un mundo y un ambiente real donde ambientarlas.

Los tiburones son criaturas increíbles que nosotros los humanos recién comenzamos a comprender. Este libro, con fotografías de cientos de tiburones y la información más reciente, animará a todos a hacer algo por estos animales en peligro de extinción.

Imagine traveling at half the speed of a jet plane without ever leaving the ground! Students will discover the technology that makes such speeds possible, from special tracks and safety precautions to aerodynamically designed trains. What are the limits to the speed of trains? What imposes those limits? Students also will read about the future of passenger train travel, from flying trains to trains that use huge magnets to levitate inches or centimeters off the track. Some trains safely reach speeds of more than 200 mph!