Cómo funcionan los ecosistemas

Oceans cover 70 percent of the Earth's surface, providing students with a variety of plant and animal life to learn about. An ocean biome includes the saltwater below the waves and everything on, above, and near the surface. Students will also learn about the beach, tides, cliffs, bays, coastlines, coral reefs, and tide pools in this Spanish-translated title.

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...

Provides a basic introduction to caves, including geographical information and plant and animal life.

An innovative tool supports high school students and teachers in the area of language and communication. PP.