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(B) The signatures of less than 10 percent of the tenants were obtained on the pet lovers’ petition.
(C) Ninety percent of the tenants are against changing the rule forbidding pets.
(D) The support of 10 percent of the tenants for a rule change ensures that the rule change will be adopted.
(E) The failure of the pet lovers to obtain the signatures of 10 percent of the tenants on their petition for a rule change ensures that the rule change will be voted down by a majority of the tenants.
16. 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 chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion ad been achieved.
Which one of the following, if true, would cast doubt on the experimenters’ conclusion?
(A) Helium-4 was not the only gas found in the experiment chamber.
(B) When fusion is achieved, it normally produces several by-products, including tritium and gamma rays.
(C) The amount of helium-4 found in the chamber’s air did not exceed the amount of elium-4 that is found in ordinary air.
(D) Helium-4 gas rapidly breaks down, forming ordinary helium gas after a few hours.
(E) Nuclear fusion reactions are characterized by the release of large amounts of heat.
17. Every photograph, because it involves the light rays that something emits hitting film, must in some obvious sense be true. But because it could always have been made to show things differently than it does, it cannot express the whole truth and, in that sense, is false. Therefore, nothing can ever be definitively proved with a photograph.
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