The red squirrel is native to the northern part of Great Britain. Recently gray squirrels have expanded into this habitat and they feed on the same food sources as red squirrels. Over time, the red squirrel population has declined severely. In some areas in Britain, red squirrels are absent and gray squirrels are abundant. Which of the following explain the phenomenon described above? Choose all that apply.

A. Population Regulation
B. Character Displacement
C. Logistic Growth
D. Density-Independent Factor
E. Niche Differentiation
F. Realized Niche
G. Competitive Exclusion Principle
H. Resource Partitioning

It is also referred to as Gause's law named after Georgy Gause, is a proposition which states that two species competitive to each other over the same resources can not co-exist stably.

The one with the slightest advantage over the other will dominate in the long run resulting in either extinction of the inferior species or to a behavioral shift of the inferior competing species towards aan ecological niche different from theirs.