Answer:
Beak shape/size or song or behavior or mechanical/chemical differences or time of mating or location on the island or primary food source differs between the Big Bird lineage and G. fortis.
Also acceptable: Description of another mechanism that prevents males and females from different populations from encountering each other/recognizing each other as potential mates.
The microscopic observations of cells form the basis of the cell theory and the idea that all living things are composed of cells; cells are the structural and functional unit of living things.
Cell membrane is the answer
To describe a scientist as skeptical, they question existing ideas and a new hypothesis. skepticism is a valuable quality because it shows that scientists is good and open minded.
i hope this helps...
D because they are complete systems
