No.
Mollusks are in the phylum mollusca.
sea stars, or starfish are in the phylum echinodermata.
In the Kingdom of the Animalia there is a dog, gorilla, lemur, sea star and sea squirt, but in the Phylum of the Animalia the sea star does not exist.
Echinodermata
echinodermata
I think its Sea Star because starfish aren't actually fish
Kingdom: Animalia Phylum: Echinodermata Subphylum: Asterozoa Class: Asteroidea
Kingdom: Animalia Phylum: Echinodermata Subphylum: Asterozoa Class: Asteroidea
star fish ,sea urchin sea ,sea cucumber .
Sea squirts are classified in the same phylum (Chordata) as humans.
I think it is the sea urchin although i might be wrong. - you are correct, a sea urchin is in the Echinodermata phylum as the sea star.
Echinoderms
No, an octopus would be an example of a mollusk (not a cnidarian).
Neither, sponges have their own phylum separate from both of those, called Porifera ('pore carriers').