Pre-thinking:Harris thinks that hybrids, which are animals that descend from two independent species, should also be extended the protections offered by international endangered-species regulations. Vogel disagrees, reasoning that this is not necessary since a hybrid species, if happens to go extinct, can always be revived by interbreeding the two parent species.
Since we are asked to identify the Vogel's underlying assumption, we need something that
a) allows the interbreeding of parent species
AND/OR
b) removes any obstacles for such interbreeding
(A) The techniques currently being used to determine whether a population of animals is a hybrid of other species have proven to be reliable.
This appears an interesting choice. If the techniques were unreliable, we may be unable to determine the exact parent species and hence may not be able to revive an extinct hybrid species. However, if the techniques were unreliable, we would be unable to determine which species are hybrid in the first place. Overall, this choice appears to go beyond the scope of Vogel's argument. Eliminate.(B) The international regulations that protect endangered species and subspecies are being enforced successfully.
Vogel's argument is concerned with interbreeding parent species and not the efficacy of regulations protecting extant species. Eliminate.(C) The gray wolf has been successfully bred in captivity.
This deals with intra-species breeding of the gray wolf and is hence not relevant to the inter-species breeding argument made by Vogel. Eliminate.(D) All hybrids are the descendants of species that are currently extant.
Correct. This assumes that all current hybrid species have parent species that are not extinct. This would allow for the inter-breeding of parent species in the event of the child species going extinct. If we negate this ie; if some hybrid species' parents species are extinct then in the event of extinction of the child species, it cannot be revived by inter-breeding the parent species since one (or both) are extinct. The argument breaks down.(E) The coyote and the red wolf are not related genetically.
This contradicts the premises given in the stimulus and hence cannot be an assumption. Furthermore, Vogel's argument is about hybrid species in general and one specific linkage or lack thereof does not impact it. Eliminate.Hope this helps.
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