Answer:
I believe the increase in the average beak depth was caused by both the increase in large-beaked finches and a decline in small-beaked finches, since due to the disappearance of the small-beaked finches, only the long-beaked finches will be taken into consideration, so the average depth of the beak will be greater. The finches with small beak depth will not be counted.
Step-by-step explanation: