Which group includes gentle aquatic herbivores like manatees and dugongs?

• A. Sirenia
• B. Polyp
• C. Porifera
• D. Polychaeta

Answer: (A)

This question tests recognizing the group of aquatic herbivorous mammals that includes manatees and dugongs. Sirenia are warm-water, slow-moving marine mammals known as sea cows. They graze on aquatic vegetation, especially seagrass, and spend most of their time grazing rather than swimming quickly. Their body shape—with paddle-like forelimbs and a horizontally oriented, paddle-like tail—and their herbivorous diet set them apart from the other options, which are a sessile Cnidarian stage (polyp), sponges (Porifera) that filter feed, and marine worms (Polychaeta). In short, sirenia are the gentle herbivores of the sea that include manatees and dugongs.