Which sentence demonstrates the correct use of an apostrophe? a sea star is an echinoderm because it’s body has five sections that are arranged around a central disk. sea star’s spines are made of calcium carbonate plates, which protect the creature from birds, fish, and sea otters. close observers will notice that, though sea stars appear to float, they’re actually propelled by tiny tube feet. sea stars have an amazing ability to drop their arms when threatened by a predator—but then regenerate new one’s.