Critical Reasoning: Conclusion Strengthening Questions

Although it is the opinion of an expert, aired in a recent radio interview, clearly the statement that our skin should constantly be protected from the sun's rays is inaccurate. There is a possibility that in the next 50 to 100 years the damage done to the ozone layer will have been corrected so that the protection that it once granted us will be restored. However, based on current evidence, harmful UV rays are penetrating our atmosphere. Still, our bodies need sunlight and UV for the synthesis of vitamin D, a vital element in our ability to defend ourselves from a variety of serious illnesses even though the benefits of skin protective products have been proven.   

Which of the following, if true, most strongly supports the above conclusion?

Incorrect.

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This answer choice neither strengthens nor weakens the conclusion. Although it presents a few details about the sun's rays and sunscreen lotion, it doesn't tell us anything thing that favors either side.

Incorrect.

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This answer choice neither strengthens nor weakens the conclusion. The fact that UVA and UVB rays have negative effects is not the issue in question. The opinion being argued against is that we should constantly use protection against such rays.

Incorrect.

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This answer choice neither strengthens nor weakens the conclusion. The fact that ultraviolet light is a dangerous thing in our current ozone-depleted situation is not at question here. The expert's opinion is that we should always, or constantly, be protecting ourselves from sunlight. The conclusion that we're supposed to be supporting opposes this opinion.

Incorrect.

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This answer choice neither strengthens nor weakens the conclusion since it revolves around refuting parameters that are irrelevant to the argument anyway. Since we are in search of parameters that are directly related to ultraviolet light, this statement is beside the point.

Impressive work!

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This answer choice strengthens the conclusion that the expert's opinion is inaccurate in two ways. Firstly, it tells us of a disease that is caused by not getting enough vitamin D which we are told by the premises is created by ultraviolet exposure. Secondly, it links ultraviolet light to the curing of the disease, showing that it is actually a necessary factor in the human biological system.

Constant and complete protection from the sun's rays means that the sunlight that our bodies would usually absorb, which spans a wavelength range of 290 to 400 nanometers, would only reach our skin after being filtered by the organic and inorganic particles in sunscreen lotion.

Of the three bands of ultraviolet light, the bands UVA and UVB, through overexposure, are the major factors responsible for sunburn, photodermatoses, the aging of skin, and skin cancer.

The behavior of skin cells is altered by ultraviolet light which changes the behavior of genes and damages DNA, leaving permanent mutations with changes in the growth characteristics of the skin, ultimately resulting in a risk of cancer.

Rickets, a disease predominant in children that was first connected to a deficiency in vitamin D by medical experts over a century ago, can be corrected with treatments of controlled exposure to ultraviolet light.

Contrary to popular belief, pollution levels, geographic location, percentage of cloud cover, and time of day are characteristics that do not directly influence parameters of ultraviolet light exposure and consequently, vitamin D levels.