After a drought on Daphne Major Island, which beak characteristic likely led to higher survival rates among Darwin's finches?

The correct answer points to the survival advantage provided by deeper beaks during the drought conditions on Daphne Major Island. During this period, food sources that were typically available to the finches became scarce. The available seeds were largely larger and harder due to the adverse environmental conditions. Finches with deeper beaks were better equipped to crack open these larger seeds, enabling them to access the food resources necessary for survival.

In contrast, finches with shallower beaks struggled to obtain food, leading to lower survival rates in that group. The resulting natural selection favored individuals with deeper beaks, which facilitated better foraging efficiency in the challenging environment following the drought. This is a prime example of how environmental pressures can shape the morphology of a species over generations, demonstrating the principles of natural selection in action.

Understanding how specific traits like beak depth directly relate to survival in changing environments helps illustrate the concept of adaptation and the dynamic nature of evolution.