Comparison of even-toed ungulate and cetaceans genetic material has shown that the closest living relatives of whales and hippopotamuses is the paraphyletic group Artiodactyla. Dan Graur and Desmond Higgins were among the first to come to this conclusion, and included a paper published in 1994.
Definition of roundâtrip. : a trip to a place and back usually over the same route.
1 A roundtrip A380 business class award between New York and Dubai would cost you 85,000 miles.  An A380 first class award from New York to Milan to Dubai to New York (with stopovers in Milan and Dubai) would cost you 135,000 miles.