« on: October 16, 2007, 12:42:04 PM »
A recent study concludes that prehistoric birds, unlike modern birds, were cold-blooded. This challenges a widely held view that modern birds descended from warm-blooded birds. The conclusion is based on the existence of growth rings in prehistoric birds' bodily structures, which are thought to be found only in cold blooded animals. Another study, however, disputes this view. It concludes taht prehistoric birds had dense blood vessels in their bones, which suggests that tehy were active creatures and therefore had to be warm-blooded.
Question stem: which one of the following, if true, would most help to resolve the dispute described above in favor of one party to it?
I couldn't decide between the two following answers, the second of which is the CORRECT answer:
D) Dense blood vessels are not found in all warm-blooded species
E) In some cold blooded species the gene that is responsible for growth rings is also responsible for dense blood vessels
If you know it, please explain why E is the correct answer, and why D doesn't help resolve the dispute by providing evidence AGAINST the study (in the last sentence) that `concluded the prehistoric birds had to be warm blooded.
Thanks in advance.