Question 10

Kittens born to the shorter, slightly heavier mothers in the colony are not less likely than average to survive to adulthood.

The investigators' conclusion about the future physical characteristics of female cats relies on the assumption that kittens born to these mothers will survive at rates comparable to the average. If the survival rates were significantly lower, the increase in the number of kittens would not lead to a sustainable population over time.

A) Birth and death rates in the colony will not change significantly over the next two hundred years.

This option addresses population dynamics but does not directly relate to the specific trend being analyzed. While stable birth and death rates may be a factor, the conclusion primarily hinges on the survival of the kittens rather than overall population stability.

B) Female cats in the colony that are shorter than average also tend to be slightly heavier than average.

This statement may describe a correlation, but it does not serve as a necessary assumption for the investigators' conclusion about future averages. The conclusion focuses on the relationship between existing physical characteristics and the survival of kittens, not on this specific correlation.

C) Kittens born to the shorter, slightly heavier mothers in the colony are not less likely than average to survive to adulthood.

This assumption is critical because it ensures that the increase in the number of kittens from the shorter, heavier mothers contributes to the population's future. If these kittens have lower survival rates, the predicted changes in the female cats' physical characteristics would not hold true.

D) Average length and weight of male cats in the colony will not change over the next two hundred years.

While the characteristics of male cats may influence the overall population dynamics, they do not directly affect the conclusion drawn about female cats. The focus of the conclusion is on female reproductive success and kitten survival, making this option irrelevant.

E) In the colony, female cats that have more kittens than average also live longer than average.

This statement does not directly support or contradict the investigators' conclusion about future averages of female cats. It may provide additional context regarding female longevity but is not essential for the assumption concerning kitten survival rates.

Conclusion

The assumption that kittens born to the shorter, slightly heavier mothers will not be less likely to survive to adulthood is vital for the investigators' conclusion regarding the future characteristics of the female cat population. Without this assumption, the predicted increase in kitten numbers would not be sustainable, undermining the conclusion that female cats will become shorter and heavier over time. Other options either address unrelated factors or do not provide necessary support for the conclusion.