Scientists are debating how to limit their newly-discovered power to change genetic
structure. Scientists already modify the genes of farm animals and agricultural plants to make
them more productive or stronger. But now they can also change genes in wild animals and
plants. These genes would continue into later generations. For example, it may be possible
for scientists to remove from existence the kind of mosquitoes that carry the Zika virus. They
might also be able to permanently remove species of plants and animals that are destructive to
other species.
In a report published last week, the U. S. National Academies of Sciences, Engineering
and Medicine (NAS) said it supports continued research on this kind of gene control. But it
warned that it is not possible to know what will happen when these changed plants and
animals are released into the wild.
Sixteen biologists, ethicists(伦理学家) and policymakers are on an NAS committee that
is examining the issue. They say that there is value to the new technology. But, they say,
there is not enough evidence to support the release of modified organisms (生物体) from the
laboratory into nature.
Many people would support stopping mosquitoes and rats from carrying diseases. But
scientists say we must understand the possible scientific, ethical, legal and social results of
such action before we decide whether to take it. Gene modification is spread through
reproduction(繁殖).
Changed genes will continue to spread as long as an animal or plant continues to
reproduce. They cannot be limited to a farm or kept within a country's borders. Scientists are
wondering what may happen if a modified organism mates with another species. They are not
yet sure how the modified genes would affect the other species. It is possible that those genes
could harm those creatures or even lead to their disappearance from our planet.
32. What possible advantage does gene control in wild animals and plants have?
A. Changing the Zika virus permanently.
B. Removing the destructive species for ever.
C. Having changed genes in their next generations.
D. Making all the species more productive and stronger.
33. As for genetically changed wild animals and plants ,what are scientists worried about?
A. They may become weaker or die out.
B. They may be more productive.
C. They may cause damage to their living habitat.
D. Their genes may spread to later generations.
34. Which of the following is NOT true according to the passage?
A. Scientists are not sure what exact results gene modification leads to.
B. Scientists won't modify any genes before they make the final decision.
C. Gene modification has benefited some farm animals and agricultural plants.
D. Scientists have not applied gene modification to wild animals and plants in case of
possible danger.
35. What can be the best title for the passage?
A. Stop research on gene control
B. How to change genetic structure
C. Power and danger of gene control
D. Advantages of gene control in wild animals and plants