Word: fossilizes
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...excited that he could hardly gasp out the news. Only five minutes' walk from the tents, he had just spotted a completely intact human-like jawbone sticking out from under a layer of volcanic rock on the shore of a dry lake. Alemayehu Asfaw figured that the fossil was at least as old as the rock-and the rock had already been dated as more than 3 million years...
While U.S. energy requirements can be met by conventional fossil fuels, research and development of alternative sources-solar and thermal energy and the like-should continue apace. Development of the fusion process should be given top priority as a replacement for the breeder reactor, which employs the riskier nuclear fission process...
...depriving the surface of solar heat. Bryson believes that the excess dust comes in part from volcanic eruptions, which seem to have increased in recent years. Still other atmosphere polluters could be: 1) extensive land clearing and deforestation by slash-and-burn techniques, and 2) the increased use of fossil fuels, which release soot into...
...Murray Mitchell Jr., argue that it may only be a random fluctuation, rather than part of any fixed cycle. In fact until a few years ago, many scientists suspected that the earth would heat up, largely because of mankind's increasing output of carbon dioxide. A byproduct of fossil-fuel burning, the gas lets sunlight pass down through the atmosphere but prevents the escape of infra-red heat waves that are radiated from the earth's surface. Thus the gas adds to the planet's heat store...
...Plutonium (Pu-239) is not found in nature, but will become increasingly abundant. It is the artificial byproduct of the fission that takes place within nuclear power generators. After complicated processing, it can be converted into a warhead, and that is what worries experts. As the soaring price of fossil fuels encourages an increasing number of nations to buy nuclear plants to generate electricity, substantial amounts of Pu-239 will become available. "There will simply be more and more tinder lying around," observes Francois Duchene, the director of London's International Institute for Strategic Studies...