18. Sommer's research concludes that cheetahs have sufficient genetic diversity to respond to common diseases, but may still be at risk of new diseases. Which statement from the passage supports this conclusion?
Answer: B
Sommer's research indicates that cheetahs have sufficient genetic diversity to respond to common diseases, but may still be at risk of new diseases.
The conclusion drawn from Sommer's research highlights that while cheetahs possess some genetic diversity, it remains less than that of other big cat species. This suggests that although they can respond to common diseases, their limited variation still places them at risk for new diseases.
A) Major histocompatibility complex (MHC) genes are used by the body to identify self from non-self...
This statement describes the function of MHC genes but does not directly address the level of genetic diversity in cheetahs or their ability to respond to diseases. Therefore, it does not support the conclusion regarding cheetahs' risk related to new diseases.
B) The variation in MHC genes in cheetahs is still smaller than that for other big cat species but appears to be sufficient...
This statement directly supports the conclusion by acknowledging that while cheetahs have some genetic variation in their MHC genes, it is not as extensive as in other big cats. This limited genetic diversity implies that they are adequately equipped to handle common diseases but still vulnerable to new ones.
C) If any of the genetic factors are different, then the immune system of the individual...
This statement discusses the implications of genetic differences in the context of organ transplants and immune response but does not provide insight into the overall genetic diversity of cheetahs or their capacity to respond to diseases. Thus, it does not support the conclusion.
D) Sommer's research determined how many alleles are present on two different types of MHC genes...
While this statement addresses the specific research conducted by Sommer, it does not directly relate to the implications of genetic diversity and the associated risks of disease. It lacks the necessary content to support the conclusion about cheetahs' genetic diversity and disease response.
Conclusion
Option B is definitive in supporting the conclusion that cheetahs have sufficient genetic diversity for responding to common diseases, yet remain at risk for new diseases due to their lower genetic variation compared to other big cat species. The other options either fail to address the question directly or focus on aspects of genetic function that do not pertain to the risk assessment outlined in Sommer's research.