单选题 Fourteen-year-old Sean MeCallum lay in a hospital bed waiting for a new heart. Without it, Sean would die. Sean's case is not unusual. Everyday many people die because there just aren't enough human organs to go around. Now scientists say they can alter the genetic make-up of certain animals so that their organs may be acceptable to humans. With this gene-altering technique to overcome our immune rejection to foreign organs, scientists hope to use pig hearts for transplants by the year 2008. That prospect, however, has stirred up strong opposition among animal right activists. They protest that the whole idea of using animal is cruel and unjust. Some scientists also fear such transplants may transmit unknown diseases to humans. Others believe transplanting animal organs into humans is unnecessary. Millions of dollars spent on breeding pigs for their organs could be better spent on health education programs. They believe seventy-five percent of the heart disease cases that had lead to a need for organ transplant are preventable. The key is to convince people to eat healthfully, and not to smoke or drink alcohol. Scientists could also use research funds to improve artificial organs. Still others believe that though new inventions and prevention programs may help, spending money to encourage more people to donate their organs is an even better idea. If enough people were educated about organ donations, everyone who needed an organ could be taken off the waiting list in a year.

单选题 What is the problem the passage begins with?

单选题 Not only is the gene-altering technique a technical issue, according to the passage, but also it______.

单选题 Doubtful of the necessity of using animal organs, some scientists______.

单选题 It can be inferred from the concluding paragraph of the passage that______.

单选题 The information the passage carries is______.