Jeri Freedman

Mountains are in constant transition despite their apparent permanence. This book explains how mountains are formed, how they evolve, and what they tell us about the history of the earth.

Tay-Sachs disease is a rare, hereditary disease that affects young children, primarily Ashkenazi Jews, French Canadians, and other isolated or self-selecting populations. Caused by the lack of an enzyme that leads to a buildup of fats in nerve and brain cells, it gradually destroys the affected cells, leading to a loss of mental and physical abilities, and, eventually, death. In this fascinating offering, ""Tay-Sachs Disease"" discusses the nature of the disease, why it affects certain groups of people more often than others, how genetic screening can help detect carriers of the Tay-Sachs gene, and what options genetic testing and counseling provide for having children. Student researchers will discover the new medical treatments being used experimentally to treat Tay-Sachs disease, as well as the new genetic treatments that may someday provide a means of curing this degenerative condition.

This book is a balanced overview of the issues surrounding stem cells and their potential to revolutionize medicine and provide cures, with a focus on the use of embryonic stem cells. The ethical and moral debates over how cells are obtained, the definition of "personhood," and various religious perspectives are explored, as well as how politics play a part in the discussion of this issue. It includes a look at stem cell research around the world and how the United States could be left behind.

Every living thing requires nitrogen to survive--and the delicate balance of the nitrogen cycle is under threat by human activity. Explore the very real and observable climatic effects of increased nitrogen levels in our atmosphere.