Explanation
Correct answer: A.
Choice A is the best answer because it most logically completes the text’s discussion of how Bing Xie and her team analyzed plains zebra vocalizations. In this context, “categorize” means to sort into groups based on shared characteristics. The text states that Xie and her team discovered that the vocalizations of plains zebras can be grouped into at least four distinct types: “snorts,” “soft snorts,” “squeals,” and “quagga quagga” calls. According to the text, the team also found that whereas snorts vary from zebra to zebra, squeals are more consistent across zebra populations. The text indicates that the researchers used machine-learning algorithms to arrive at these findings. This context supports the idea that the researchers used the algorithms to categorize recorded vocalizations.
Why the other choices are wrong
Choice B
Choice B is incorrect because in this context, “extend” would mean to make longer or greater in size. The text discusses the researchers’ use of machine-learning algorithms to study recorded zebra vocalizations and identify patterns among the different types of calls that the researchers had recorded, not to lengthen or increase the size of the recordings.
Choice C
Choice C is incorrect because in this context, “collapse” would mean to break down or combine into a smaller form. The text indicates that the researchers used machine-learning algorithms as part of a process that yielded findings about distinct types of zebra vocalizations, suggesting that the researchers used the algorithms to distinguish among vocalization types, not to combine them.
Choice D
Choice D is incorrect because in this context, “suppress” would mean to hold back or eliminate. The text indicates that the researchers used machine-learning algorithms as part of a process that yielded findings that zebra vocalizations can be classified into four distinct types, not that the researchers used the algorithms to hold back or eliminate the vocalizations themselves.