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 answer is A, 'a mammal' because it goes with the copulative verb 'to be', i. e., 'is'.
I would try to eat more healthily because eating certain foods are a huge magnet to toxic waste and gas. This creates more pollutions and destroys the o-zone. Another thing it to take my bike instead of car or use a hybrid or an electric car if it is to far ( my destination) for a bike. Cooking food in my house with an oven is MUCH better for the clean air as well for the coal and charcoal used for grill, and wood for fires, causes a massive pinpointed area of smoke and destroy the air causing bug leaks of hydrogen in the air molecules.
what you mean in this question?