sentence: Some crabs also live in fresh water, or live completely on land.
sentences_before: It is folded under its body, and may not be visible at all unless the crab is turned over. Usually they have a very hard exoskeleton. This means they are well protected against predators. Crabs are armed with a single pair of claws. Crabs can be found in all oceans.
concept_name: crab
headings: Crab Structure and life-style Body