Hi there,
We have to select an answer choice that both gordan and earlier scientists(1970-1980) should agree.
A ---> Agreed by gordan. But we have no evidence that earlier scientists agreed to this
B ---> Agreed by earlier scientists, But we have no evidence that gordan and later scientists agreed to this
C ---> Agreed by both gordan(any change in working conditions affects the role) and earlier scientists (age can lead to change in roles)

Hope this helps!!

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.”

Q10 Did we rule out option B because the question asks for something both gordon and early researchers agree on and not just one? If that is the case then how did we conclude that earlier researches agreed about external factors? The passage credits the research to 'subsequent' researchers and not early earlier researchers.
Please help me resolve this!

For question 10 a, presence in the nest of workers of different shapes and sizes, each suited to a particular task. doesn't these "variant" lead to disruptions and therefore 10 a is also correct? for both earlier researchers and gordon?

The actual researches found that a disruption in the ant nest will force them to change tasks. However, in the passage, nothing suggests that PREVIOUS researchers did the same investigations The stem says

It can be inferred from the passage that Gordon and earlier researchers would agree with which of the following statements about worker ants?

Read carefully. This is the FIRST mistake the students do.

The literally DO NOT read what is written there with attention