Complex sentence: On a synoptic scale, geological units coincide with topographical units, to begin the country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields.
Split into simpler sentences: On a synoptic scale, geological units coincide with topographical units. The country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields.