Starfish? what is its real purpose?

Question

what adaptations do starfish make and how is it useful in their environment

Answer 1

They can throw out their stomach and digest food externally.

How cool is that!

Answer 2

Their stomach is able to extend through their "mouth" and into its surroundings to perform extracellular digestion. Also, on each of its "feet", there are things called tube feet, which are basically thousands and thousands of little tiny suckers which can adhere to a surface very strongly. These tube feet come in handy when tides are extremely strong, or a low tide is present. The sea star is able to anchor itself securely to a surface, preventing it from being washed away or falling off of a cliff when there is no water present. The stomach is very handy when it comes to feeding. Clams and oysters are very strong at keeping their shells open, so sea stars must use their tube feet, push them open, and then digest the clam in its own shell. Also, the sea star has a water vascular system, which is useful because it's surrounded constantly by water. This helps in locomotion when little jets of water can be squirted out of the tube feet as well.

And starfish is a scientifically incorrect name, as sea stars are echinoderms and fish are a chordate. Just a little heads up =)