Wikipedia reported that the animal Kingdom is divided into 9 major phyla as shown in the image to the right.[1] The 9 major phyla shown on the chart continue to subdivide into a final 35 phyla.[2] Carl Linnaeus organized life forms by their overall similarity with other life forms. For example, lizards and snakes are both reptiles. Look at the 9 animal phyla chart on the right. Compare Sea-Monkeys with the nine types of animal in the taxonomy tree. Which animal on the chart is the Sea-Monkey is the most similar too. If you concluded that Sea-Monkeys looked most similar to the crab, you are correct. Sea-Monkeys are Arthropoda. An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and paired jointed appendages.[3] Invertebrate means having no backbone. So, Sea-Monkeys belong to the crab family of animals.
[1] MS. ANDERSON'S ZOOLOGY CLASS, http://msandersonzoo.weebly.com/phyla.html (accessed 2021-01-18)
[2] Wikipedia, List of animal phyla, https://simple.wikipedia.org/wiki/List_of_animal_phyla (accessed 2021-01-18)
[3] Wikipedia, Arthropod, https://en.wikipedia.org/wiki/Arthropod (accessed 2021-01-18)