Lipids are long chains of carbon and hydrogen molecules. They are oily or waxy.
Proteins are large molecules consisting of one or more chains of amino acids. They provide structure and support for cells.
Carbohydrates are mainly sugars and starches that the body breaks down into glucose. They are the main source of energy in animals.
Nucleic acid is an important class of macromolecules found in all cells and viruses. The functions of nucleic acids have to do with the storage and expression of genetic information.
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.
