Question

Each area on sea urchins/sand dollars has 2 rows of what?

Answer 1

Sea urchins and sand dollars have 2 rows of tube feet in their unique internal structure called a test.

Step-by-step explanation:

Sea urchins and sand dollars have 2 rows of tube feet. These tube feet are part of their unique internal structure called a test. The tube feet are used for slow movement and to keep their body surface clean. Sea urchins and sand dollars do not have arms but have a radial symmetry with their tube feet arranged in five rows.