Fairly sure that would be secondary succession.
Answer: The observation "A" leads us to conclude that the finches populations are from two different species
Explanation:
According to the biological concept of species, <em>a set of individuals are from the same species if they are able to reproduce and leave fertile offspring</em>. This is key so one species can be successful and perpetuate through time. If they cannot leave descendants, then the species will be extinct. However, it’s possible that two individuals from different species mate and have descendants, but they cannot leave fertile offspring. When they are from different species, the offspring will be sterile and it is called a hybrid.
In the case of the South American finch, the island's finch population and mainland's finch population belong to different species because their offspring is sterile. To have different features, as different feather's color, or to have other dietary preference is not enough to say that they are different species. This is because within the same species, individuals can have variations. For example, we can different eye color and belong to the same species.
Carried on the X or Y chromosomes
