题目内容：

For thousands of years, mankind has produced plants and animals to create more desired and useful plants and animals. For example, modern com has been produced to such a large size that it is no longer able to reproduce without man’s assistance. Modern dairy cows produce too much milk and if they are not often emptied of milk, they could leak, burst, become infected, and possibly die. Besides, most dogs raised by people can not survive in the wild even with special training.

Since natural evolution is extremely slow and mankind’s selective production programs only take a few generations to produce a completely new species, natural evolution has already taken a back seat to mankind’s production programs. In addition, mankind has successfully killed off several species all together. For example, there are no more European wolves in existence and mammoths (猛犸象) probably died out because of mankind. Even certain diseases have been permanently got rid of from the planet, and dozens of other diseases will soon be too. Again, natural evolution did i»t cause most of the destruction during man’s rule of the world.

Currently, scientists are creating new species with desired characteristics in the lab significantly faster than natural evolution creates new species. In a single generation, new species can be created and destroyed by mankind, while natural evolution could take thousands of years to do the same but only accidentally. Scientists are even able to replace defective (有缺陷的) or damaged genes with different genes to attempt to cure genetic defects. This is something that natural evolution could possibly never correct.

Eventually scientists will even be able to improve the quality of people. For example, imagine not only correcting your eyesight with gene treatment, but also ensuring that all of your children do not receive your old genes of poor eyesight too. Scientists will one day be able to improve the memory and intelligence of your children, so that they will do better in school and achieve more in life. Doctors and scientists will be able to customize (订制) babies before they are born just like picking options at a car store.

1.According to the first paragraph,______ .

A. man-made evolution has improved all species

B. man-made evolution has weakened some species

C man-made evolution can make up for all natural losses

D. natural evolution won’t happen without man’s assistance

2.What does the underlined part “taken a back seat to” in Paragraph 2 mean?

A. Become powerful assistance to.   

B. Become a huge barrier to.

C Speeded up the process of.   

D. Played a less important role than.

3.What does the third paragraph mainly talk about?

A. Why natural evolution happens so slowly.

B. The way scientists adopt to have genetic defects repaired.

C. The advantages of man-made evolution over natural evolution.

D. How scientists make use of man-made evolution to create new species.

4.What can we infer from the passage?

A. Near-sighted parents will be able to produce babies with good eyesight in the future.

B. Doctors and scientists will be responsible for mass production of babies in the future.

C. It is natural evolution that is to blame for the destruction of European wolves and mammoths.

D. Children can now have their memory and intelligence improved with the help of gene treatment.