Nuclear fusion is a process whereby the nuclei of atoms are joined, or “fused,” and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using “heavy” water contained in a sealed flask. The flask was, in turn, contained in an air-filled experimenters cited this evidence in support of their conclusion that fusion had been achieved.
What this question is testing
Your task
Find the choice that makes the argument's conclusion less likely to be true.
Common trap
Answers that look negative but attack a claim the argument never relied on.
Winning move
Find the assumption the argument depends on, then pick the choice that undermines it.
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