Ecdysozoansprotostomes are categorized into two clades: lophotrochozoa and ecdysozoa. ecdysozoa includes about eight phyla, including the phyla arthropoda and nematoda. arthropods and nematodes (roundworms) are among the most abundant of all animal groups. the simplified evolutionary tree below shows the relationship between arthropods, nematodes, and lophotrochozoans. (there are more ecdysozoan phyla than shown on this tree.)part a - comparing nematodes and arthropodsnematodes and arthropods are the largest ecdysozoan phyla. which of the following statements are true? select all that apply. the cuticle in nematodes lengthens as the animal grows. arthropods are named for their jointed appendages. nematodes are acoelomate, whereas arthropods are coelomate. both nematodes and arthropods possess an external covering, or cuticle. some nematodes are parasitic on humans. arthropods possess an open circulatory system. both nematodes and arthropods must molt in order to increase in size. both nematodes and arthropods have segmented body plans. nematodes possess a closed circulatory system.