Final answer:
The preacher's healing effort on Straight Beak would result in more birds with large, broad beaks surviving and reproducing.
Step-by-step explanation:
The result of the preacher's healing effort on Straight Beak would be to have more birds with large, broad beaks surviving and reproducing.
In the scenario described, there was a drought and fewer seeds were available for finches to eat. Birds with smaller beaks could only crack open and eat the smaller seeds, while birds with bigger beaks could crack and eat seeds of all sizes. As a result, many small-beaked birds died in the drought, while birds with bigger beaks survived and reproduced. Over time, this would lead to an increase in the average beak size in the finch population.