Marine biologists have long thought that variation in the shell color of aquatic snails evolved as a protective camou...
cassidyarandaMay 17, 2020
Answer choice C vs. D
are the wave actions discussed in C. irrelevant and that is why this answer is incorrect because in the passage mentions wave action and its relation to stress which is why i choose C over D and am confused about this one point
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The traditional theory discussed in the passage attributes the variation to camoflauge, noting that brown shells are found on dark-colored seafloor whereas white shells are found on light-colored seafloor. The new theory attributes the variation to heat absorption (which changes depending on wave action), noting that brown shells are found in areas of great wave action/minimal heat absorption whereas white shells are found in areas of low, calm wave action/more heat absorption.
However, how do we know that the theories don't overlap? Perhaps all areas of great wave action have dark-colored seafloor and all areas of low, calm wave action have light-colored seafloor.
The question asks for evidence that would support the new theory over the old one. This means that we will want to show a case where the relationship between wave action/heat absorption and shell color from the new theory is present but the relationship between seafloor color and shell color from the traditional theory is not present.
(C) "light-shelled snails in an inlet with much wave action and a dark, rocky bottom" This is incorrect because, although it shows that the seafloor color expected by the traditional theory is not the case, it also shows that the expected wave action/heat absorption from the new theory is not occuring. Therefore, (C) does not support the new theory. In fact, it casts doubt on both theories.
(D) "light-shelled snails in a calm inlet with a dark, rocky bottom and many predators" This is correct because it casts doubt on the traditional theory by showing light-shelled snails on a dark seafloor. At the same time, it supports the new theory by showing light-shelled snails in a calm (low wave action) area.
Does that make sense? Please let us know if you have any other questions!
