Final answer:
Sea arches and a blowhole on the Australian Tasman Peninsula were formed by erosion from waves.
Step-by-step explanation:
Sea arches and a blowhole on the Australian Tasman Peninsula were formed by erosion from waves. Over time, the relentless force of the ocean waves gradually eroded the rock formations, creating the sea arches and blowhole. The constant pounding of the waves weakens the rock and eventually wears away the softer layers, creating an arch or hole.