Today, medicine is increasingly concerned with transplant surgery, in which an organ from one person is placed into the body of another because it can often extend the patient's lifespan and improve his quality of life. Thus, there is a large demand for replacement organs. __________.As a result, in some countries, children are being kidnapped and killed in order to provide an illegal source of organs. At the same time, to get desperately needed money, poor people in some Third World countries are selling spare organs, such as kidneys, from their own bodies.
For centuries, scientists and philosophers have speculated on the structure of the universe and the existence of galaxies outside our own. But until the twentieth century, they were able to do no more than speculate. __________ .Using giant telescopes, ultraviolet and infrared instruments, and high-speed computers, they are studying the information of galaxies for further insights into the nature of the cosmos.