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Questions 1 - 7
(1) Both tissue transplants and organ transplants are used in the treatment of disease. Tissue transplants include the transplanting of skin, bones, and the cornea of the eye;
whereas organ transplanting includes replacing a kidney, heart, lung, or liver. Skin and cornea transplants are very common and successful, and have been performed for
(5) hundreds of years. In fact, there is evidence that skin transplants were done as early as 600 B.C. in India. Organ transplants, on the other hand, are quite recent. They are also more difficult to perform. Moreover, it is not always easy to find a suitable donor. Even if a healthy organ is found, the receiver's body may reject it. This is the major reason for problems with organ transplants.
(10) The first heart transplant was performed by Dr. Christiaan Barnard in 1967 in South Africa. Many successful heart transplant operations have been performed since then. In 1982, Dr. Barney Clark was the first to receive al') artificial heart. Research into organ transplants continues all the time. Doctors are continuing to find new ways to combat the problems, and to make transplants safer and more available to people who need
(15) them.
Questions 8 - 14
(1) Harvesting ice sounds like a new concept, but actually it has been around for years. Scientists have been studying this idea as a possible solution to the problem of the world's dwindling fresh water supply. Ninety percent of the earth's fresh water is in the icecaps of Antarctica. If only 10 percent of that ice could be towed to civilization, it
(5) could provide water for 500 million people. But the problem, of course, is one of melting. How can a giant iceberg be towed across the sea without melting? The answer could lie in enclosing the floating ice in a huge cylindrical container made of a high-strength synthetic fabric. If the iceberg is nudged into the fabric container, which is opened at both ends, then the ends can be sealed and the sea water pumped out.
(10) After that it can be towed to civilization. The melting rate will be slowed down, and the synthetic cocoon will act as a holding tank for the water. Engineering this project, which might include a container up to one kilometer in length and 100 meters in diameter, would be a feat, but engineers say it is possible. After all, fishermen in north Australia sometimes use nets 8 kilometers long and 20 meters across.
