4 Crustaceans are herbivores, carnivores, or scavengers and are often vital elements of the food chain.
(4 Crustaceans; are; herbivores, carnivores, or scavengers) (4 Crustaceans; are; T:often; vital elements of the food chain)
4 Crustaceans 4 Crustaceans
are are
herbivores, carnivores, or scavengers
T:often vital elements of the food chain