Here's why:

* Isolated mass: Sea stacks are separate from the mainland, standing alone.

* Rising steep rock: They are often tall and vertical, formed from resistant rock.

* Near coastline: They are typically found close to the shore, often in groups.

How sea stacks form:

Sea stacks are created by erosion. Waves relentlessly pound the coastline, gradually eroding cliffs and creating caves. Over time, these caves can break through to the other side, forming arches. Eventually, the arch can collapse, leaving an isolated column of rock – the sea stack.

Let me know if you have any other details about the rock formation you're interested in, and I can give you a more specific answer!