Critical Reasoning

Two types of earthworm, one black and one red-brown, inhabit the woods near the town of Millerton. Because the red-brown worm's coloring affords it better camouflage from predatory birds, its population in 1980 was approximately five times that of the black worm. In 1990, a factory was built in Millerton and emissions from the factory blackened much of the woods. The population of black earthworms is now almost equal to that of the red-brown earthworm, a result, say local ecologists, solely stemming from the blackening of the woods.

Which of the following, if true, would most strengthen the conclusion of the local ecologists?


A. The number of red-brown earthworms in the Millerton woods has steadily dropped since the factory began operations.

B. The birds that prey on earthworms prefer black worms to red-brown worms.

C. Climate conditions since 1990 have been more favorable to the survival of the red-brown worm than to the black worm.

D. The average life span of the earthworms has remained the same since the factory began operations.

E. Since the factory took steps to reduce emissions six months ago, there has been a slight increase in the earthworm population.


OA C

Source: Veritas Prep