【单选题】

The passage is chiefly concerned with
A．(A) offering an explanation of the process that causes a phenomenon, and a counter-explanation

B．(B) demonstrating how two processes act in symbiotic coordination in causing a phenomenon
C．(C) establishing how one process causes a phenomenon which is resisted by a second process
D．(D) explaining two separate processes which cause a mostly identical phenomenon
E．(E) outlining the essential differences between two distinct phenomenon that issue from a single cause