Answer:
If a population of medium ground finches with large, deep beaks colonizes a nearby island where Tribulus cistoides is the most abundant food for the next 1000 years, it is expected that this finches population will dominate de island, displacing the smaller beaked birds.
Step-by-step explanation:
Since large seeds will be available for the next 1000 years as the most abundant food, only birds with large beaks will be able to eat them. Smaller beaked birds won´t be able to feed on them, and eventually, they will starve because they won´t have any food. In this way, the finch population will rapidly change on the new island in favor of the medium ground finches with large, deep beaks.