Neither option 2 (both the same size) nor option 3 (both are mollusks) is correct. Option 1 (both are invertebrates) is partially correct, as both starfish and snails lack a backbone or vertebral column, making them invertebrates. However, the better answer is option 4: both are echinoderms. While snails are classified as mollusks, starfish belong to a separate phylum called Echinodermata, which includes other animals such as sea urchins and sand dollars. Echinoderms are known for their radial symmetry and unique water vascular system.
The correct characteristic that is common to a starfish and a snail is that they are both invertebrates.
