Mashaal Masha
North American gray wolves usually have mixed gray and white fur, but some members of the species have a version of a gene, or gene variant, that gives them a mostly black coat instead. Sarah Cubaynes and her team studied twelve populations of North American gray wolves. They found that the black-furred wolves are more common in areas where outbreaks of distemper virus happen regularly. The team also discovered that the black-furred wolves are more likely to be immune to distemper than the gray-furred wolves are. Taken together, these findings suggest that _______

Which choice most logically completes the text?
Difficulty: Easy
A: 

North American gray wolves experience more outbreaks of distemper virus than other wolf species do.

B: 

the gene variant that results in black fur may be linked to immunity to the distemper virus.

C: 

the average life span of gray wolves is likely to increase over time because of a particular gene variant.

D: 

gray-furred wolves will soon replace black-furred wolves across North America.