"Los invisibles"

Who were the earliest Americans? When, how, and from where did they enter and spread across the continent? And what is their relationship to modern Native Americans? Anthropologists develop theories to answer these questions based on the evidence they discover. Their theories—and the discoveries that prove and disprove them—are highlighted in this fascinating volume, full of awe-inspiring facts and incredible breakthroughs. Readers will feel like anthropologists and archaeologists themselves as they read about bones and artifacts, and what they reveal about the ancient cultures that roamed...

Updated for 2020, the months of the year are taught through engaging text and photos that symbolize each month.

Learn all about the amazing things your brain does and how to keep it healthy and strong! Readers will discover the anatomy of the brain including neurons, the cerebellum, and the nervous system. Using vibrant images and informational text in conjunction with supportive diagrams, this Spanish-translated nonfiction title encourages readers to learn all about (and use) their brains.

Con la conquista de los cielos, el ser humano ha puesto a prueba su fisiología, llevando a su organismo hasta límites impensados. Con el avance en el vuelo, el cuerpo se ha visto cada vez más expuesto a diferentes situaciones que comenzaron a causar afecciones fisiológicas en todo su organismo. Cambios te presión, cambios de temperatura, exposición a radiación, entre otro. Fisiología aeronáutica es una obra dedicada al estudio y análisis de las principales afecciones a las que el organismo humano se ve expuesto durante las actividades u operaciones aéreas. Es importante que el...