El ciclo del nitrógeno (The Nitrogen Cycle)

Como es sabido, el diseño surge como consecuencia lógica del desarrollo industrial de las sociedades tecnológicamente más avanzadas y puede explicarse, por tanto, en función de esa relación causa-efecto. Sin negar su obvia dependencia de tiempo y lugar, las razones del diseño, sus lecturas e interpretaciones, no se agotan en el exclusivo ejercicio metonímico, desde fuera, sino que invitan a ser entendidas también desde dentro, a partir de su propia realidad física y la reflexión que en ellas palpita. El libro adopta este criterio en su parte esencial: emparentar realizaciones...

As a successful former slave, Clara Brown used her money to help other freed slaves get a new start in life. In 1859 Clara bought her own freedom and headed west to Colorado to find her daughter, who was sold when she was just a little girl. Clara didn't find her daughter there, but she did get rich. The people she helped became her family, and she became known as "Aunt" Clara Brown.

Bright stars twinkle in the night sky. Have you looked up into the sky on a clear night and seen these tiny points of light? Did you know that there are many kinds of stars in space? Find out all about them in this Spanish-translated book.

Grouping and classification are among the first math and science skills that children need to learn. This fun book will challenge children to observe natural creatures to see what makes them the same and different. It presents an interesting way of looking at objects, because the objects may not be exactly the same. For example, birds have two wings, but the wings of different birds may not look similar.