Which group of arthropods can be distinguished from other groups by their calcium-containing,hardened exoskeleton and mostly marine habitat?

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Quizplus · Accepted Answer

Crustaceans are the group of arthropods that have a calcium-containing, hardened exoskeleton and are mostly found in marine habitats. Insects have a chitinous exoskeleton and are found in a variety of habitats including land, air, and water. Millipedes have a softer exoskeleton and are mostly found on land. Chelicerates have a chitinous exoskeleton and are found in a variety of habitats including marine, freshwater, and terrestrial environments. Trilobites, although also having a hardened exoskeleton, are extinct.

Which Group of Arthropods Can Be Distinguished from Other Groups