2. The best part about being multicellular is that cells can become _________and there is a division of labor.

3. __________________________are the first great innovation in the animal body plan.  

4. __________________________are groups of similar cells that are organized into a functional unit.

5. Most animals have some type of __________________________.

6. _________________= wheel-like; can slice it like a pie and each piece is similar; ex. sea anemone, starfish

7. ______________________= left and right half is similar; ex. humans

8. __________________________are bilaterally symmetrical, cephalized, and have organs.

9. __________________________is when a definite head end develops in an organism.

10. A/An _________________is an animal without a body cavity. Ex. flatworm

11. A/An ____________is an animal with a body cavity between the mesoderm & endoderm.  Ex. roundworm

12. __________________________are animals with a body cavity inside the mesoderm.  Ex. mollusk

13. __________________________were the first animals with segmented bodies.

14. Arthropods developed __________________________.

15. Arthropods have an __________________________to support their bodies.

16. ___________are animals that develop according to signaling by molecules in different parts of the egg.

17. __________________________are animals that develop according to genes inside the cells.

18. All chordates have 3 characteristics at some point: _______________, a dorsal nerve chord, and pharyngeal slits.

19. Most chordates are __________________________ that have a sturdy endoskeleton 
 
 

20. ESSAY: What is meant by the phrase “division of labor?”