B.8(B) 19 A student collected the animal shown below on a field trip. The student used a dichotomous key and a microscope to classify the animal, Step 1a Possesses segmentation Dichotomous Key Characteristic Identification Go to 2 Go to 3 Phylum Arthropoda Phylum Annelida 1b Lacks segmentation 2a Has an exoskeleton with jointed appendages Has no exoskeleton, unjointed appendages (if any present), and a segmented worm- like body; is possibly in a tube (if in a tube, may have tentacles) 2b 3a 3b Possesses a foot, a radula, arms, and/or a shell Lacks all of the above and is dorsoventrally flattened Phylum Mollusca Phylum Platyhelminthes © iStockphoto.com/Nancy Nehring How should this animal be classified? A Arthropoda B Annelida C Mollusca D Platyhelminthes ​