Scientists say that, by bathing the skin cells in extracts of immune cells, that human skin cells in a test tube are made to behave as if they were immune system cells.

Analysts and media executives predict the coming year to be no less challenging than the previous one had been for the company’s C.E.O.

Educator Maria Montessori believed that students be allowed to choose from among a number of different lessons designed for the encouragement of their development as thinkers and creators with individual learning and thinking styles.

In the United States, less than half as many multifamily housing units were produced in the 1990s than in each of the previous two decades.

Officials at the United States Mint believe that the Sacagawea dollar coin will be used more as a substitute for four quarters rather than for the dollar bill because of its weight, only 8.1 grams, which is far less than four quarters, which weigh 5.67 grams each.

Although when a hagfish is threatened, it will secrete slime that is small in quantity, it expands several hundred times as it absorbs seawater, forming a slime ball that can coat the gills of predatory fish and either suffocate them or distress them enough to make them flee.

Dinosaur tracks show them walking with their feet directly under their bodies, like mammals and birds, not extended out to the side in the manner of modern reptiles.

By skimming along the top of the atmosphere, a proposed new style of aircraft could fly between most points on Earth in under two hours, according to its proponents.

Upon their first encountering leaf-cutting ants in South America, the insects seemed to some Europeans to be carrying bits of greenery to shade themselves from the tropical sun--hence the sobriquet "parasol ants.”

Although the earliest inhabitants of Mapungubwe, building their dwellings of either wattle and daub or unfired mud brick, by the thirteenth century buildings of coral blocks in lime mortar began to appear.