Agujeros negros (Black Holes)

SHAAAARRRKK! That's probably the last word anyone wants to hear while swimming in the warm blue sea. But most sharks aren't at all what people expect. In fact, those who think all sharks are giant, man-eating killers are in for a surprise. The compelling narrative, colorful illustrations, and captivating facts in SURPRISING SHARKS reveal that sharks come in all shapes and sizes - and probably should be more afraid of humans than we are of them. Back matter includes a note about sharks and an index.

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...

Un libro de referencia para todas las preguntas que chicos y chicas se hacen sobre el sexo, aunque les resulta incómodo hablar de ello. Con textos escritos por profesionales, serio, riguroso, pero al mismo tiempo ameno y divertido. Porque la mejor protección es la información.

Practice nonstandard measurement at the zoo! This exciting, Spanish-translated title encourages readers to practice measuring their favorite zoo animals, such as elephants, giraffes, pandas, and more. A gorilla weighs the same as three men! When a cheetah runs, its stride length is the length of three men! An elephant weighs the same as three pickup trucks! Vivid images, fun practice questions, early STEM themes, and helpful mathematical diagrams make nonstandard measurement entertaining and easy for children to understand.