Question statement:

Fears, initially widespread in the general public, that genetic engineering of new biological products would produce an ecological disaster- some uncontrollable new organisms have proved unfounded.

In the few years since such work began, substances of great medical value have been produced, and no disaster has resulted.

To do: Weaken the argument

Pre-Thinking: The statement starts off by saying that fears that some people hold about the genetic engineering of new biological products are unfounded. The reasoning is that in this short period of time, there has been no such disaster.

We have to find a loophole in this reasoning. What if the time taken for the ecological disaster to happen is a lot more than has currently elapsed since the work began? In that case, we can surely say that the fear might not be unwarranted.

Also, what if the author's information about the absence of any disaster is incorrect? Can there be a possibility that some disaster has occurred and the author is not aware of it?

NO
Always remember we can only doubt the line of reasoning, not the facts presented. "No disaster has resulted" is a fact that we have to take for granted. We can't doubt it.

On going through the answer choices, we find that (A) fits our line of reasoning perfectly and is the correct choice.

(B) This is actually a strengthener. It says that work till now has happened under strict safety guidelines. We cannot assume that in the future, this might not be true. This statement gives us no reason to believe that the future research may be different from the present. Incorrect choice

(C) The reactions of the citizens does no harm/good to the argument. It is out of scope.

(D) The argument is about the benefits or ill effects of genetic engineering. Are we concerned about what several cities have done? No!

(E) This choice talks about what might happen after this new organism is created. We are concerned about the very fact whether such an organism might be created. Incorrect choice.

Answer: A