.... long journey is now often interrupted by hydroelectric plants. Hydropower is a very good alternative resource for power, however it is very damaging to our salmon populations. The dams block off rivers, which block the salmon's path back to their breeding grounds. The salmon go back to the same areas, just as their ancestors did, to lay their eggs. The hydropower plant's turbines are also very dangerous to young salmon. Many of them are killed by the giant turbines on their way back to the ocean. Killing off many of the salmons new generation. Pollution is also a killer of many Chinook salmon. Pollution caused by sewage, farming, grazing, logging and mining find it' ....

.... not amount to creating a "carbon copy"— an automaton of the sort familiar from science fiction. It would be more like producing a delayed identical twin. And just as identical twins are two separate people—biologically, psychologically, morally and legally, though not genetically—so a clone is a separate person from his or her non-contemporaneous twin. To think otherwise is to embrace a belief in genetic determinism—the view that genes determine everything about us, and that environmental factors or the random events in human development are utterly insignificant. The overwhelming consensus among geneticists is that genetic determinism is false. As geneticists hav ....

.... studied its properties, which coincided those that Dmitrii Ivanovich Mendelev had predicted a few years earlier for eka-aluminium, the then undiscovered element lying between aluminum and indium in his periodic table. Though widely distributed at the Earth's surface, gallium does not occor free or concentrated in independant minerals, except for gallite. It is extracted as a by-product from zinc blende, iron pyrites, bauxite, and germanite. Silvery white and soft enough to be cut with a knife, gallium takes on a bluish tinge because of superficial oxidation. Unusual for its low melting point ( about 30 degrees C, 86 degrees F ), gallium also expands upon solidification ....

.... about vectors, strands of DNA like viruses, which can infect a cell and insert themselves into its DNA. With this knowledge, scientists started to build vectors which incorporated genes of their choosing and used the new vectors to insert these genes into the DNA of living organisms. Genetic engineers believe they can improve the foods we eat by doing this. For example, tomatoes are sensitive to frost. This shortens their growing season. Fish, on the other hand, survive in very cold water. Scientists identified a particular gene which enables a flounder to resist cold and used the technology of genetic engineering to insert this 'anti-freeze' gene into a tomato. This mak ....

.... reef. There are three types of coral reefs: fringing reefs, barrier reefs, and atolls. Fringing reefs are located close to shore, separated from land by only shallow water. Barrier reefs lie farther offshore, separated from land by lagoons more than ten meters deep. Atolls, on the other hand, are formed far offshore and they make a ring-shaped reef that close a circular lagoon. Coral reefs are the largest biological structures on the planet, with the largest being the Great Barrier Reef covering over 2000 kilometers along the East Coast of Australia. The reef is said to be 500,000 to 2,500,000 years old and is said to be visible from the moon. There is only one problem w ....

.... With the discovery of the ozone hole in the 1980's attention was now more focused on the threat humans were posing to the environment. With scientific evidence to back up pessimistic predictions of our future, most people, through media coverage, political pressures and general concern now see the environment as being truly threatened by human progress and in desperate need of help. Natural hazards have been defined as “...extreme geophysical events greatly exceeding normal human expectations in terms of their magnitude or frequency and causing significant damage to man and his works with possible loss of life.” (Heathcote,1979,p.3.). A natural hazard occurs when the ....

.... Microscopic Organisms 1. Archaebacteria 2. Rickettsiae Microbiology What is Microbiology? Microbiology is the study of microorganisms. This includes protozoans, algae, fungi, bacteria, viruses, and rickettsiae. A microbiologist is a scientist who studies life forms that can only be observed by means of a microscope. Microbiologists use many criteria to classify bacteria. The Beginning of Microbiology Zacharias Jansen created the microscope. Although Robert Hooke is the one who made it widely known. In 1665 Hooke published a book called Micrographie. It contained his thoughts on chemistry as well as a description and list ....

.... are like human fingerprints; no two have the same pattern of stripes. The tiger's head often carries the Chinese mark of wang or king on the forehead. Most have an orange coat with dark brown or black stripes accented with white. that live in cold climates (Siberian ) have thicker fur than that live in warm climates. A tiger's tail is 3 to 4 feet long, about half as long as its body. use their tails for balance when they run through fast turns. They also use their tails to communicate with other . Where did tigers come from? Tigers (and all other carnivores) are descended from civet-like animals called miacids that lived during the age of the dinosaurs about 60 millio ....