Migratory birds which are unable to fly long distances without resting have to use the shortest distance over water in their flights to and from Africa, and so they cross at the Straits of Gibraltar. It is essential for these birds, some of which are very rare, that the route remains open. For that reason, it is important that plans to build electricity-generating wind farms on the hills surrounding the Straits of Gibraltar do not go ahead.
Which one of the following is an assumption on which this argument depends?
A. The birds that migrate across the Straits of Gibraltar are close to extinction.
B. Electricity-generating wind farms have to be built on hills.
C. The planned wind farms will make it dangerous for migratory birds to use their route.
D. Other species of bird can fly further and can thus use other routes in their migration.
E. There are no plans to build wind farms at other places along the coast.
- Identify the question type. Although not phrased in the typical Cambridge format (“What is the assumption in the argument…”) we can easily identify that it is asking for an assumption.
- Strategy Tool Kit for solving assumptions
Find the conclusions
Find the reasons
Find the unwritten link that the conclusion relies on
Discard and decide (use negation test if needed) any invalid options and you’ll have your answer
When solving assumptions, we are trying to see what piece of information in the answer choices is absolutely necessary for there to be a strong argument in the text. The easiest way to do this is to do the negation test, which reverses the answer by saying the opposite and analysing the outcome. Lets look at the answer options:
A. Negation test: If these bird were not extinct, would anything change? No because if these electricity-generating wind farms are dangerous for the bird populations, many will be affected and it could put strain on their populations as well (even if healthy at first). It should not matter whether the birds are endangered or not, it could have a grave effect on the population. Because there is effect regardless of wether or not the birds are instinct, this cannot be the assumption.
B. Negation test: If they did not have to be on hills, would this change anything? No, because the text does not specific the flight path of the birds (i.e it does not say if they only fly over hills or if they fly in a valley, etc…). Regardless of wind farm placement, there is not enough information to prove it will not affects the birds in one place more than another, therefore this cannot be the assumption.
C. Negation test: if the wind farms did not make it dangerous for migratory birds, would it change anything? Yes! If the wind farms are not dangerous for the birds to use this route, then why does it matter if the farms are here? This would greatly weaken the conclusion that these farms should not be built here because its a migratory route. Therefore this is the correct answer.
D. Without even using the negation test we can see this answer is just a distractor. We know that other birds can fly further and thus probably use different routes, it says so in the text. This is not our focus, we are focusing on the birds that need to cross in this one area (Straits of Gibraltar) and what the effects are if wind farms are added. Therefore this answer is irrelevant and incorrect.
E. This is another distractor that is not relevant. It does not matter what is happening in other regions at the moment because our focus is on the effect of the straits of Gibraltar. What changes if there is or is not wind farms at other places along the coast? Nothing. There will still be a potential danger to birds crossing in these straits. Therefore this answer is incorrect.
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