Complete Question Explanation
Assumption. The correct answer choice is (E)
The stimulus attempts to counter the proponents of organic farming who claim that using chemicals harms wildlife. The stimulus argues that organic farming requires the use of more land, so organic farming reduces habitat available for wildlife.
The argument is unconvincing. First of all, habitat does not necessarily compensate for poisoning. Secondly, there is no good reason to suppose that animals cannot use farmland for habitat.
Since you are asked to identify a necessary assumption, you need to locate a choice that links habitat and poisoning, or a choice that links farmland to a loss of habitat.
Answer choice (A): The argument does not need to assume that chemicals pose no threat to wildlife, the argument only needs to assume that chemicals pose less of a threat to wildlife than does habitat loss.
Answer choice (B): The argument does not need to assume that wildlife is unaffected by chemicals, the argument only needs to assume that the chemicals negatively affect the wildlife less than does the loss of habitat.
Answer choice (C): Since the argument only concerns wildlife, whether chemicals have effects on things other than wildlife is a non-issue. Assumptions on non-issues are not essential to an argument.
Answer choice (D): The argument does not need to assume that the crops grown organically and chemically are currently identical in order to make the land-use observation that it does. Even if the crops cultivated organically differ greatly from those cultivated chemically, the argument's observations about land usage can be correct, so this assumption is inessential.
Answer choice (E): This is the correct answer choice. One of the linking assumptions that the argument must make is that farmland means a loss of wildlife habitat, so this choice delivers a necessary assumption.