Sentence Correction (SC) | Re: Some bat caves, like honeybee hives, have residents that

Hi,
cant we look at the structure like this- X,Y, and Z
here X= defending the entrance, Y= acting as sentinels and sounding a warning at the approach of danger Z= , and scouting outside...
Notice that there is no comma before and sounding a warning. and there is a comma before the 3rd element in the list ie. Z( , and scouting outside).
So, basically
...

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