The authors of a recent article examined warnings of an impending wave of extinctions of animal species within the next 100 years. These authors say that no evidence exists to support the idea that the rate of extinction of animal species is now accelerating. They are wrong, however. Consider only the data on fishes: 40 species and subspecies of North American fishes have vanished in the twentieth century, 13 between 1900 and 1950, and 27 since 1950. Which one of the following is the main point of the argument? ['A substantial number of fish species are in danger of imminent extinction.', 'The rate of extinction of North American fishes is parallel to the rate of extinction of all animal species taken together.', 'There is evidence that the rate of extinction of animal species is accelerating.', 'Forty species and subspecies of North American fishes have vanished in the twentieth century.']