Joseph Connell discovered that Balanus barnacles were excluded from the upper intertidal zone by ____________, while Chthalamus barnacles were excluded from the middle intertidal zone by ___________.
A. competition from mussels, prolonged immersion in water
B. competition from mussels, competition with Balanus
C. prolonged exposure to air, competition with Balanus
D. prolonged exposure to air, competition with algae
E. predation by wading birds, predation by starfish
