The name of the landform remaining after a sea arch collapses is a sea stack.
The name of the landform remaining after a sea arch collapses is a sea stack. To find this answer, you can start by understanding what a sea arch is. A sea arch is a natural rock formation formed along coastal areas, where the force of erosion has worn away the rock to create a hollow arch-like structure. When a sea arch collapses, the arch portion of the formation collapses, leaving behind a vertical column of rock that is separate from the coastline. This vertical column is called a sea stack. So, the correct answer is "sea stack."