【单选题】So too did a lot of the norths soldiers. One of the central themes of the political history of the twelfth century was the continual effort by the northern kingdoms to extend their control southward i...
A.
To highlight the difference between the views of various ecologists about the nature of ecological communities
B.
To illustrate why some ecologists tended to view ecological communities as highly integrated
C.
To demonstrate that one forest has a greater variety of species than the other
D.
To show how these two forests differ from others in the United States