Wait, with the ants question i think two answers were very similar. One was saying that the author is assuming what consitutes individual members applies to the whole, and the other said the author is assuming what applies to the whole must apply to its constituent parts.
I think I answers the latter, because I recall the stimulus ending with "therefore no ants can't successfully spread" or something like that, which I interpreted to mean the author is assuming just because ants as a whole are successful at spreading, then each particular species of ant must be, thus no ant species can't be. What do you think?