Whales originated in the freshwaterlakes and rivers of ancient Asia about sixtymillion years ago. Not until about tenmillion years later did species of whales develop specialized kidneys enablingthem to drink salt water. Althoughfossil evidence shows that some early whale species that lacked such kidneyssometimes swam in the Earth’s saltwater oceans, these species must have had toreturn frequently to freshwater rivers to drink.
GWD27-Q22:
Whales originated in the freshwaterlakes and rivers of ancient Asia about sixtymillion years ago. Not until about tenmillion years later did species of whales develop specialized kidneys enablingthem to drink salt water. Althoughfossil evidence shows that some early whale species that lacked such kidneyssometimes swam in the Earth’s saltwater oceans, these species must have had toreturn frequently to freshwater rivers to drink.
Which of the following is moststrongly supported by the information given?
A. Fossils of whale species dating from betweensixty million and fifty million years ago will not be found on continents thatwere at the time separated from ancient Asiaby wide expanses of ocean.
B. Among whale fossils that date from laterthan about fifty million years ago, none are fossils of whale species thatdrank only fresh water.
C. Fossils of whale species that drank freshwater will not be found in close proximity to fossils of whale species thatdrank salt water.
D. The earliest whales that drank salt waterdiffered from fresh-water-drinking whales only in their possession ofspecialized kidneys.
E. Between sixty million and fifty millionyears ago, the freshwater lakes and rivers in which whales originated weregradually invaded by salt water.
A，貌似是对的，可是假如有一小部分whales在600到500万年前生活在例如海口很近的海里，可以再海里游泳，然后回淡水区喝水，不也有可能在之前是海现在时大陆的地方发现化石么。。。。求讨论
-- by 会员 UCLA2011 (2010/12/7 6:03:56)