A、An industrial trial in Spain. B、Military trials in Spain and Sweden. C、Industrial trials in Spain and Sweden. D、A trial involv

About 10 million people in the U.S. alone, from troops returning from war to students with music lasting through headphones are suffering from impairing noise-induced bearing loss. The rise in trend is something that researchers and physicians at the University of Michigan Cresgo Hearing Research Institute are hoping to reverse, with the cocktail of vitamins and the mineral magnesium that shall promise as a possible way to prevent hearing loss caused by loud noise. The nutrients were successful in laboratory test. And now researchers are testing whether humans will benefit as well. The combination of vitamins A, C and E plus magnesium is given on pill form to patients who are participating in the research. Developed at the UM Cresgo Hearing Research Institute, the medication, called Oral Quell, is designed to be taken before a person is exposed to the loud noise. Until a decade ago, it was thought that noise damaged hearing by intense mechanical vibrations that destroyed delicate structures of the inner ear. There was no intervention to protect the inner ear other than reducing the intensity of sound reaching it, such as ear plugs which are not always effective. It was then discovered that noise caused intense metabolic activity in the inner ear and production of molecules that damage the inner ear cells. And that allow the discovery of intervention to prevent these effects. The laboratory research that led to a new understanding of mechanisms underlying noise-induced hearing loss was funded by NIH, the Preclinical Translation Research that led to the formulation of Oral Quell as effective preventative was funded by General Motors and the United Auto Workers. Now Oral Quell is being tested in a set of four multinational human clinical trials, military trials in Sweden and Spain, and industrial trials in Spain and the trial involving students at the University of Florida who listen to music at high volumes on their iPods and other PDAs.
Questions:
21. According to the talk, how many victims of hearing problem are there in United State alone?
22. Which did UM Cresgo Hearing Research Institute develop to prevent hearing loss?
23. According to the latest findings, what does loud noise damage?
24. According to the talk, who supported the lab research?
25. Which of the following is not included as the multinational human clinical trials for Oral Quell?