Explanation

9) Choices A and B are correct. The question asks about the factors considered to affect ant roles in the earlier period under discussion. Describing the period from the 1970s to the mid-1980s, the passage states that “Other elements then considered to have primary influence upon an ant’s career were its age … and its genetics.” Choice C is incorrect: the passage never discusses ants’ experiences outside the nest

10) Choice C is correct. The question asks about points that Gordon and earlier researchers would agree on. Choice A is incorrect: Nest disruption is an external factor favored by later researchers such as Gordon, but there is no suggestion that earlier researchers considered it a factor. Choice B is incorrect: Earlier researchers might have thought that genetics was a predominant factor, but the later work showed that other factors could override
genetics. Choice C is correct: Both earlier and later researchers knew that an individual worker ant can change its role. According to the passage, the earlier researchers thought that an ant “might change tasks as it got older,” and later researchers “were able to change the tasks performed by individual workers.”

11) Choice C is correct. The question asks about the role of the last sentence. Choice A is incorrect: the passage never mentions any experiments performed by earlier researchers. Choice B is incorrect: the last sentence simply describes the experiments and their results but does not make any attempt to justify their methodology. Choice C is correct: the experiments described in the last sentence show that ants’ roles in the nest can be affected by external conditions, and Gordon is described in the passage as “advocating this approach.”