单选题 The passage is chiefly concerned with

• (A) offering an explanation of the process that causes a phenomenon, and a counter-explanation
• (B) demonstrating how two processes act in symbiotic coordination in causing a phenomenon
• (C) establishing how one process causes a phenomenon which is resisted by a second process
• (D) explaining two separate processes which cause a mostly identical phenomenon
• (E) outlining the essential differences between two distinct phenomenon that issue from a single cause