Question

exclusively inhabiting tropical countries such as ghana, wild chimpanzees lack adaptations to seasonal variations in ultraviolet b (uvb) irradiance from sunlight since uvb exposure enables vertebrates to synthesize vitamin d. sophie moittié and colleagues studied zoo chimpanzees in spain and other mid - latitude countries to see how vitamin d levels are affected by the seasonal variations in uvb irradiance that occur in those locations. they found that chimpanzees vitamin d levels were significantly lower in autumn than in summer and appeared unaffected by oral supplementation of vitamin d administered by zookeepers. moittié and colleagues point out, however, that supplementation was rare, highly varied, and poorly tracked, and therefore
which choice most logically completes the text?
a. the effect of supplemental vitamin d on zoo chimpanzees in spain and other mid - latitude countries can more clearly be observed in summer than in autumn.
b. the possibility that zoo chimpanzees in spain and other mid - latitude countries would benefit from supplemental vitamin d during autumn cannot be excluded.
c. vitamin d levels in zoo chimpanzees in spain and other mid - latitude countries may be higher during autumn than moittié and colleagues data appear to indicate.
d. differences in vitamin d supplementation likely explain more of the difference in vitamin d levels across zoo chimpanzees in spain and other mid - latitude countries than seasonal differences in uvb irradiation do.

Explanation:

The text states that vitamin D supplementation was rare, highly varied, and poorly tracked. This means that the data on its effect is not reliable. Option B is logical because it acknowledges that despite the current data (which may be flawed due to poor tracking of supplementation), the possibility of benefit from supplementation cannot be ruled out. Option A is incorrect as the text doesn't suggest a clearer observation in summer. Option C goes against the data presented (vitamin D levels were lower in autumn). Option D is not supported as the text emphasizes the problem with supplementation tracking rather than comparing supplementation and UVB effects.

Answer:

B. the possibility that zoo chimpanzees in Spain and other mid - latitude countries would benefit from supplemental vitamin D during autumn cannot be excluded.