DAT Review Questions (Dental Admissions)

Answer: A, Natural selection. Giraffes with longer necks have a distinct survive advantage over those with shorter necks.

Key Takeaway: A key component of natural selection is that changes that are beneficial will win out over changes that are less beneficial. In this case, giraffes with longer necks are able to reach more food than those with shorter necks. This means those giraffes are more likely to be healthy, and more likely to produce offspring, since reproduction requires a certain level of physical health.