Only a Few Species of Garter Snakes (Thamnophis Atratus, Th

Multiple Choice

Only a few species of garter snakes (Thamnophis atratus, Th. couchii, and Th. sirtalis) have evolved the ability to tolerate a toxin produced by newts called tetrodotoxin (TTX) . The phylogeny below shows how these three species are related. Referring specifically to Th. couchii and Th. sirtalis, tolerance to TTX is an example of a ______ caused by _______.

A) reversal; homology
B) homology; convergent evolution
C) homoplasious trait; convergent evolution
D) homoplasious trait; homology
E) ancestral homology; natural selection