题目： Day Length and Reproductive Timing in Animals For many animals, producing offspring at a time of year when a maximum amount of food is available is essential. Producing yo...

Igloos   In the language spoken by the Inuit-an indigenous people inhabiting the Arctic regions of Canada, Greenland, and the United States-the word 'igloo' means 'house' or '...

Deer Antlers and Seasonal Mating 题目：   In temperate (moderate)climates and subpolar regions (those nearer to the poles), where winters are usually long and the vegetation ...

The Proto-Indo-European Language     Scholars have known for several centuries that most of the languages spoken in a broad swath from Britain to India are derived from ...

Benefits of Migration Why do animals migrate? One obvious answer is to escape cold weather by moving to a warmer region. Each fall, millions of monarch butterflies migrate southw...

Were Dinosaurs Endothermic   题目： Because dinosaurs are considered reptiles, they were for many years thought to be cold-blooded (ectothermic) like modern reptiles, requiri...

Developing Sustainable Pesticides   题目：   Pesticides are substances used to get rid of insects or other pests. A pesticide gets a bad name if, as is usually the case,...

Dating Archaeological Objects     For contemporary archaeologists who need to know the age of any objects they study, perhaps the most precise and yet technologically ...

题目： Magma   Magma is a mixture of molten (melted)and semi-molten rock and other solids found beneath Earth's surface.Melting in Earth requires very specific conditions:the...

Deer and the Forests of Kinkazan 题目： The ancient beech forests of Kinkazan Island off the coast of northern Japan are in danger of disappearing. Few beech saplings (young tree...