Explanation
Correct answer: A.
Choice A is the best answer because it most accurately describes the overall structure of the text. The text first presents what researchers found from studying Matabele ants: the ants can tell when colony members have infected wounds and can largely successfully treat those infections with their antimicrobial secretions. The text then indicates that the findings about the ants could help with the future development of antibiotics for humans. Thus, the text summarizes research findings and then identifies an area for further research.
Why the other choices are wrong
Choice B
Choice B is incorrect. Although the text introduces a study about Matabele ants, it never discusses how the researchers did their work or any methods they used to produce their findings.
Choice C
Choice C is incorrect. Although the text does describe properties of Matabele ants—their ability to detect and largely successfully treat infected wounds in colony members—it never addresses evolution or how these properties might have changed.
Choice D
Choice D is incorrect because the text doesn’t present anything about Matabele ants as an issue or problem to be solved. Instead, it discusses beneficial abilities the ants have (detecting and treating infected wounds) and suggests that understanding those abilities might be useful for human medicine.