Which boundary type forms mountains when plates collide?

• A. Convergent boundary
• B. Divergent boundary
• C. Transform boundary
• D. Fossils

Answer: (A)

Mountains primarily form when two continental tectonic plates collide at a convergent boundary. The collision thickens and deforms the crust, causing rocks to buckle and push upward into tall, rugged ranges—an effect well seen in the Himalayas where the Indian and Eurasian plates meet. When a oceanic plate meets a continental plate, the oceanic slab usually sinks beneath the continent (subduction), but the resulting intense compression and crustal deformation can still build mountains and sometimes volcanic activity, though the classic high mountain belts typically come from continental-continental collisions. Divergent boundaries create new crust as plates move apart, often forming mid-ocean ridges or rift valleys rather than tall mountain ranges. Transform boundaries slide past each other and mainly cause earthquakes with little uplift. Fossils is not a boundary type.