Critical Reasoning

The importance of the ozone layer to terrestrial animals is that it entirely filters out some wavelengths of light but lets others through. Holes in the ozone layer and the dangers associated with these holes are well documented. However, one danger that has not been given sufficient attention is that these holes could lead to severe eye damage for animals of many species.


Which one of the following is most strongly
supported by the statements above, if they are true?
(A) All wavelengths of sunlight that can cause eye
damage are filtered out by the ozone layer
where it is intact.

(B) Few species of animals live on a part of the
earth's surface that is not threatened by holes
in the ozone layer.

(C) Some species of animals have eyes that will not
suffer any damage when exposed to
unfiltered sunlight.

(D) A single wavelength of sunlight can cause
severe damage to the eyes of most species of
animals.

(E) Some wavelengths of sunlight that cause eye
damage are more likely to reach the earth's
surface where there are holes in the ozone
layer than where there are not.



why options B & C are wrong?

I find that when handling most strongly supported questions one is best off just reading the prompt and going straight to the answer choices, as various things could be supported by the prompt, and so seeking to prethink the answer is usually a waste of time and can even send one in the wrong direction.

(A) All wavelengths of sunlight that can cause eye
damage are filtered out by the ozone layer
where it is intact.

This is not supported. The prompt merely says that some wavelengths are filtered by the ozone layer.

(B) Few species of animals live on a part of the
earth's surface that is not threatened by holes
in the ozone layer.

The prompt merely says that many species could be affected. It does not give any indication of what proportion of species could be affected. Many could be most, some, or a small fraction of the species that live on earth.

(C) Some species of animals have eyes that will not
suffer any damage when exposed to
unfiltered sunlight.

While the prompt does not say that all species will be affected, nowhere does it provide any clear reason to believe that some animals have eyes that will not suffer any damage when exposed to unfiltered sunlight.

(D) A single wavelength of sunlight can cause
severe damage to the eyes of most species of
animals.

The prompt discusses "some wavelengths" of light and does not single out any particular wavelength.

(E) Some wavelengths of sunlight that cause eye
damage are more likely to reach the earth's
surface where there are holes in the ozone
layer than where there are not.

The prompt says first that the importance of the ozone layer is that it filters out some wavelengths of light. That statement serves to restrict the importance of ozone to its filtering of wavelengths of light.

Then the prompt says that these holes could lead to severe eye damage for animals of many species, implying that where there are holes there is danger of eye damage greater than that where there are not holes.

So the discussion is about wavelengths of light and the holes increase danger of eye damage. So the prompt supports the idea that increased danger of eye damage is the result of ozone holes allowing wavelengths of light to reach animals.

So the best answer, and really the only one supported at all, is E.