The Quiz: The guest stars in today’s photo are called blue linckia. Which is true of sea stars?
A They’re invertebrates
B They’re crustaceans
C They’re herbivores
Starfish aren’t fish, which is why marine biologists usually prefer to call them sea stars. They’re marine invertebrates, some of the first animals to evolve at least half a billion years ago. Invertebrates are generally soft-bodied animals that lack a rigid internal skeleton but often have a hard outer skeleton. They make up more than 90% of all animal species on Earth.
The correct answer to this quiz is They’re invertebrates.