Answer:
The correct answer is option d. "Many species that moved into North America from South America outcompeted the endemic taxa and still exist today".
Explanation:
The Great American Biotic Interchange (GABI) was an historical period at which numerous species from South America migrated to North America, and numerous species from North America migrated to South America because of the formation of the Isthmus of Panama. During this event, many species that moved into North America from South America outcompeted the endemic taxa and still exist today. The species that successfully immigrated to South America and exist today were mostly small mammals, such as armadillos and opossums.
The more extreme winter storms in the Southern United States will result in change of behavior or migration of the animals that live there. The reason for that is that the animals, in this case the birds, will not be able to get to enough food, so they will have to move to a region that will provide enough food for them to survive. These birds are used to mild winters and sufficient amount of food, but the more extreme winter conditions bring in temperatures that are not suitable for the birds, and on top of that the food sources will be damaged. This will force the birds to migrate further south, toward Mexico or Central America where the winter conditions would be much better for the birds and they will be able to sustain their populations.
The tunica externa (New Latin "outer coat"), also known as the tunica adventitia (New Latin "additional coat")(or adventitia for short), is the outermost tunica (layer) of a blood vessel, surrounding the tunica media. It is mainly composed of collagen and, in arteries, is supported by external elastic lamina.
