答案　D　[主旨大意题。阅读短文可知，这篇短文主要讲述了克隆技术在防止濒危动物灭绝方面的重要作用，短文围绕一只被克隆的野生山羊而展开，故选项D"克隆技术使得一个已经灭绝的物种复活了一小会儿"符合本文主题。]

Authors Kyle Kurpinski and Terry D．Johnson pretty much have me convinced that human cloning is quite possible and is a future certainty. Kurpinski and Johnson are both bioengineering experts; unlike similar scientists you have seen in the movies，they both have a sense of humor. What surprises me is that Kurpinski and Johnson are able to take something as complicated as DNA and make it understandable.

The book How to Defeat Your Own Clone teaches us what is now known as DNA­encoded，how that happens，and why people with similar DNA don't look or act the same. The book not only helps us get a basic understanding of what DNA and its purpose are，but also explains cloning and stem cell(干细胞) research. It occurs to me that a lot of people who are against stem cell research don't know what they are protesting about. The authors provide a history of cloning，as well as information about stem cells.

The real fun starts when the authors attack various myths about cloning. Obviously，too many people have been watching too many bad movies and television programs. Remember they're just fictional stories. If，somehow，scientists manage to clone you，twenty years from now your clone isn't going to kill you. Among the myths explored and exploded are that a clone will know everything you know and will act as you do，that heads which are cut off can be kept alive，and that a clone has no belly button(肚脐)．Many of the myths are ridiculous but many people believe them.

Kurpinski and Johnson also detail some bio­improvements"that really work"．You see，genes can be controlled to help you sleep better and become smarter，healthier，and taller. Well. . . not exactly you，but future generations.

If you do wind up in a battle with your own clone，who will be considerably younger than you，remember that it is not you and that it doesn't know what you know.

5．Which of the following things are in the book How to Defeat Your Own Clone?