_ is found in the exoskeleton of crabs

Explanation

Option B is correct. Chitin is found in the exoskeleton of crabs. Chitin is a tough, fibrous material that is made up of long chains of sugar molecules. It is the main component of the exoskeletons of insects, spiders, crabs, and other invertebrates. Chitin is also found in the cell walls of fungi and some algae. The other options are not found in the exoskeleton of crabs: Cellulose is a tough, fibrous material that is made up of long chains of sugar molecules. It is the main component of the cell walls of plants. Murein is a polymer made up of two sugar molecules and a short peptide chain. It is the main component of the cell walls of bacteria. Hemicellulose is a polymer of sugar molecules that is found in the cell walls of plants.