Recognize that all organisms are composed of cells and that many organisms are unicellular and must carry out all life functions in one cell. 3.1.6.A5 Describe basic structures that plants and animals have that contribute to their ability to make or find food and reproduce.
Crabs are crustaceans and all crustaceans belong to the taxonomic domain of Eukarya, which are characterised by having cells with nuclei. Eukarya covers all organisms in the Kingdom Animalia, as well as the Kingdoms Plantae, Fungi and Protista.
Crabs are not arachnids; they are crustaceans. Arachnids are animals such as spiders. Arachnids, insects and crustaceans all belong to the family group arthropod. Arthropods are animals with exoskeletons, segmented bodies and jointed legs.They are the largest group of animals on Earth.Most crustaceans such as the crab are aquatic animals living in either marine or fresh water environments.rachnids, insects and crustaceans all belong to the family group arthropod. Arthropods are animals with exoskeletons, segmented bodies and jointed legs. They are the largest group of animals on Earth. Most crustaceans such as the crab are aquatic animals living in either marine or fresh water environments.