Read the Following Scenario and Answer the Question Below

Read the following scenario and answer the question below.
The western United States contains a series of tall mountain ranges that also extend far down into Mexico. The largest of these ranges are the Rockies and the Sierra Madres, but they are all part of the same mountain -building event that occurred many millions of years ago, and they all have similar features. However, the biodiversity of the southernmost mountains has more connection to that of Central America, while the biodiversity of the Rockies shares more affinity with temperate North American species. Still, much of the forest vegetation on these mountaintops is the same, or very similar, and they are often referred to as the ʺSky Islandsʺ because of their similarity to each other and their isolation from the lower, often drier, areas surrounding them. With global climate change producing increasingly visible effects, conservation biologists fear that these mountaintop ecosystems will undergo major changes in temperature and humidity and that the many endemic species that live there may literally have no place to go.
-Regarding the geography of Sky Islands, it is likely that _____________.

A) there is more biodiversity in the southern end of the mountain ranges because of the latitudinal gradient
B) there is more biodiversity in the northern end of the mountain ranges because of the milder climate
C) no accurate claims about relative biodiversity can be made
D) the biodiversity is patchy because of the altitudinal gradient
E) the biodiversity is evenly distributed through the mountains that stretch from Central America up through the Rockies into Montana, Idaho, and Canada