Question

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?
choose 1 answer
a gray - furred wolves will soon replace black - furred wolves across north america.
b the gene variant that results in black fur may be linked to immunity to the distemper virus.
c north american gray wolves experience more outbreaks of distemper virus than other wolf species do.
d the average life span of gray wolves is likely to increase over time because of a particular gene variant.

Explanation:

To solve this, we analyze each option:

• Option A: The text says black - furred wolves are more immune and common in distemper - prone areas, so gray - furred replacing black - furred is illogical.
• Option B: Black - furred wolves are more common in distemper - prone areas and more immune to distemper. This suggests the gene variant for black fur may be linked to distemper immunity, which is a logical conclusion.
• Option C: The text only talks about North American gray wolves, no comparison with other wolf species is given.
• Option D: The text focuses on black - furred and gray - furred wolves' immunity to distemper, not on the average lifespan of gray wolves.

Answer:

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