The abdomen of a crab can be similar to abdomen of a crayfish as they both belong to Crustaceans group of the phylum Arthropoda and have segmented abdomen. The abdomen of the crab is found below the thorax (or cephalothorax) covered under the exoskeleton.
Crustaceans are a group of Arthropoda that are normally found in water habitat. Their body is majorly divided into two parts, called: the cephalothorax and the abdomen.
Abdomen is the region of the body that generally contains the digestive organs like the stomach, liver, pancreas, etc. Apart from digestion, abdomen is also involved in respiration activity.
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