Which of the sentences below best expresses the essential information in the highlighted sentence in paragraph 4? Incorrect choices change the meaning in important ways or leave out essential information. A. Ecologists studied how the geographic characteristics of the eastern slope of the Sierra influenced the social development of chipmunks. B. Ecologists learned exactly how chipmunk species separated from each other on the eastern slope of the Sierra relate to one another. C. Ecologists discovered that chipmunks of the eastern slope of the Sierra invade and occupy higher elevational zones when threatened by another species. D. Ecologists studied how individual chipmunks of the eastern slope of the Sierra avoid interacting with others of their species.