Dichotomous Key

1) a. has symmetry -go to- 2
b. no symmetry -go to- 8

2) a. radial symmetry -go to- 3
b. bilateral symmetry -go to- 4

3) a.have no true skeleton -go to- 8
b.ahve mesodermal endoskeleton -go to-10

4) a. segmented -go to- 5
b. unsegmented -go to- 6

5) a. exoskeleton -go to- 9
b. lack of hard skeleton -go to-10

6) a. has a shellor beak -go to-11
b. lack of shell or beak -go-to- 7

7) a. one body opening -go-to- 9
b. two body openings -go-to-11

8) a. Porifera
b. Cnidaria

9) a. Platyhelminthes
b. Arthropoda

10) a.Echinodermata
b. Annelida

11) a.Mollusca
b. Nematoda