Read the paragraph. Sand dollars live on the seafloor. They eat plankton and crab larvae. They use spines and grippers on their body’s surface to capture this food. Then tiny hairs transport the food to a central mouth on their bottom side. The mouth has a jaw to grind up the tiny food particles. Food may take two days to digest.

What is the central idea of the paragraph?

Sand dollars have complicated bodies that make it difficult to hunt for food.
Sand dollars dive down deep to find plankton, crab larvae, and sea creatures.
Sand dollars use their body features to capture, transport, and eat food.
Sand dollars are clever because their mouths are hidden from their predators.