Known to be antisocial birds, cuckoos are solitary animals that practi

However, the ani species of cuckoo is highly social =>
all other species are antisocial and are categorised so because they plant their eggs in others’ nests.

Any behaviour of Ani species that shows it does not lay eggs in others nest is the correct answer. Only Answer B fits our requirement.

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OFFICIAL EXPLANATION:

Reading the question: the prompt leaves some questions unanswered. Cuckoos usually are antisocial parasites. But ani cuckoos are social--are they parasites? The answer to that question doesn't leap out. Furthermore, there is the question of the "living conditions"--what are they?

Creating the filter: of these questions, the most important, we can conjecture, is what exactly these living conditions are. The parasite business is irrelevant, perhaps, and we are talking about the question of antisocial versus social, which will depend on the living conditions. Clarifying that would add further "support" to the "scientists' explanation." So we can use "living conditions" as a basic relevance filter.

Applying the filter: choice (A) gives us genes, not living conditions, so it doesn't pass the filter. Choice (B) looks relevant--it discusses living conditions and resolves the mystery about whether ani cuckoos are parasites. So (B) stays in. Choice (C) appears to be true of all cuckoos, so it does nothing to explain the difference among them. Choice (C) is out. Ditto for (D) and (E). We're left with (B) only.

Logical proof: when you're reasonably certain on a question or running behind on time, you'll want to skip the logical proof step. Applying the negation test whenever possible on Critical Reasoning questions may be too time-consuming; you can skip it selectively to balance time management and accuracy. However, we can apply the negation test to (B). Say that ani cuckoos did not nest communally. In such a case, they might well be brood parasites, like other cuckoos. And in such a case, their living conditions, so far as we know, would not be communal. The negation of (B) would severely weaken the argument, so (B) strengthens the argument.

The correct answer is (B).

Reasoning of the argument: cuckoo is an anti-social bird species; however, the ani species of cuckoo is different. It is resonated that the influence of communal living conditions has altered its behaviours.

So, in order to weaken the conclusion of the argument, the answer choice should give new info that possibly correlate the behaviour of different species and living condition.

B. The more social species of cuckoo nest communally; a number of females lay their eggs in the nest and usually share the responsibility of incubation and feeding.---->B is correct since it brings up another perspective that the author fails to consider and that creates the logical gap in the argument. The info in this answer choice will surely weaken the argument and fill the logical gap.

ACE out of scope and D moreover weakens saying that cuckoo also have communal environment.