To accurately determine which statement best describes the difference between the two giraffe populations, a comparison of their heights and the variability within each population would be necessary. However, without specific data or study results, it's impossible to definitively select one of the provided options.
If, for example, a study found that giraffes in the wild had a wider range of heights due to factors like food availability and competition, then option (a) would be correct. Conversely, if the data indicated a more uniform height in the protected environment of the nature preserve, option (b) might be correct.
Similarly, if it was established that wild giraffes tended to be shorter on average due to environmental stresses, option (c) would apply, while option (d) would be correct if they were found to be taller on average.
If you have specific findings or context from the study, I can help interpret those results! Otherwise, it remains ambiguous which choice is correct based on the options alone.