Hi,
Let's break it down:
1. What do we need to do? We need to find an option that significantly weakens the statement that "Genetic engineering will not product an ecological disaster." 2 variables have been used to come to this opinion: production of substances of great medical value, occurence of disasters.
2. Prethinking what some weakeners could look like: either of these above variables actually have negative side effects that will nullify or outweight the positive value. For e.g. Let's say that while there has been production of substances of great medical value it has led to drug overuse, and rise in deaths due to OD (overdose)
3. Lets come to your doubt now on A) and D): A) is clear in what it implies - not enough time has passed for us to know/see the harmful side effects since the work has begun.
D) Even if some cities have banned production within their boundaries - this doesn't help us undermine: i) substances of medical value have been produced/will continue to be produced ii) no disasters.
>> The reason for rejecting D) is not that "not all possible scenarios have been tested. " It is because it doesnt directly weaken the conclusion - even if there are restrictions, the conclusion can still hold.
We have no information on what D) implies on whether all scenarios have been tested so we cannot say.
>> Hope this helps!
aasthudragonpixie
Hello, I am having trouble understanding how options A and D differ in terms of their final inference, i.e., not all possible scenarios have been tested. In D, if genetic engineering is prohibited in some places, does that mean all possible scenarios are not being tested?