Explanation
Choice D is the best answer. The experiment was to test whether crows could recognize a feature between different objects. The text claims that the crows repeatedly chose the card with the same-sized squares, indicating that they can recognize the feature between the two circles and two squares of the same size. Since they achieved this feat without a neocortex, the result would suggest that a neocortex is not necessary to demonstrate such an ability.
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Choice A: The experiment in the text does not make distinctions between younger crows and older crows.
Choice B: This answer choice contradicts the finding in the text that crows without a neocortex successfully recognized a shared feature between different objects.
Choice C: The text does not establish varying difficulty levels for animals with a neocortex and animals without it.
✨ Expert's Tip ✨
Identify the aim of the experiment: to test whether crows without a neocortex have the same ability as mammals with a neocortex. Then, recognize the researchers’ finding that crows without a neocortex have the same ability as mammals with a neocortex.