**Core Concept:** Vocabulary - Word meaning differentiation **Answer Key:** A **Analysis:** - **A. Origin** directly refers to the starting point or source (e.g., 'the origin of life'). - **B. Original** describes something being first or earliest in form (e.g., 'original manuscript'). - **C. Orientation** relates to positioning or alignment (e.g., 'map orientation'). - **D. Opponent** means a competitor/adversary (e.g., 'chess opponent'). **Common Mistake:** Confusing 'origin' (source) with 'original' (first version).