Bioluminescent beetles called ﬁreﬂies may seem to create ﬂashes of light randomly, but each species of ﬁreﬂy actually has
its own special series of repeated ﬂashes and pauses. These unique ______ allow ﬁreﬂies of the same species to ﬁnd each
other.
quantities
decorations
patterns
agreements
Choice C is the best answer because it most logically completes the text’s discussion of the ﬂashes created by ﬁreﬂies. In
this context, “patterns” means distinct and predictable sequences. The text indicates that although the ﬂashes that ﬁreﬂies
produce appear to occur randomly—that is, without any particular sequence or rhythm—each species actually produces its
own special series of ﬂashes and pauses. Indeed, these series of ﬂashes are so unique that ﬁreﬂies can use them to ﬁnd
other members of their species. Therefore, this context supports the idea that ﬁreﬂies produce ﬂashes in distinct and
recognizable patterns.
Choice A is incorrect because “quantities” means certain amounts or numbers of something. Although the text discusses
how different ﬁreﬂy species produce ﬂashes and pauses in unique sequences that help other members of their species to
ﬁnd them, it doesn’t mention the number of ﬂashes that are used in these sequences. Choice B is incorrect because in this
context, “decorations” would mean things that make an object more beautiful. Although it may be reasonable to say that
ﬁreﬂy ﬂashes are beautiful, the text focuses on the fact that ﬁreﬂies use these unique sequences of ﬂashes to ﬁnd other
members of their own species, not that the ﬂashes make ﬁreﬂies more beautiful. Choice D is incorrect because in this
context, “agreements” would refer to deals that individuals have discussed and come to a consensus about. Since ﬁreﬂies
aren’t capable of making such agreements, it wouldn’t make sense to use this word to refer to the signals they send each
other with their ﬂashes.