Question ID:PT57 S3 Q24 Passage:It is widely believed that lancelets‚ small, primitive sea animals‚ do not have hearts. Each lancelet has a contracting vessel, but this vessel is considered an artery rather than a heart. However, this vessel is indeed a heart. After all, it strongly resembles the structure of the heart of certain other sea animals. Moreover, the muscular contractions in the lancelet's vessel closely resemble the muscular contractions of other animals' hearts. Stem:The argument's conclusion follows logically if which one of the following is assumed? Correct Answer Choice:CChoice A:Only animals that have contracting vessels have hearts. Choice B:Some primitive animals other than lancelets have what is widely held to be a heart. Choice C:A vessel whose structure and actions closely resemble those of other animal hearts is a heart. Choice D:For a vessel in an animal to be properly considered a heart, that vessel must undergo muscular contractions. Choice E:No animal that has a heart lacks an artery.