1 Complete Summary Table A.1 in the Appendix, filling in the characteristics of cnidarians in the appropriate row. 2 What specialized cells in Hydra aid in capturing and subduing prey? 3 What structures determine whether a polyp of Obelia is a feeding polyp or a reproductive polyp? 4 Speculate about the selective advantage of radial symmetry and a diffuse nerve net for sessile and free-floating animals such as sea anemones and jellyfish. 5 What modification do sea anemones possess that allows food and water to be distributed among the partitioned regions of their bodies? 6 Match the class with the correct organism or characteristic. Hydra Obelia sea anemone jellyfish no medusa form; only polyp comb jelly medusa form dominant; polyp greatly reduced both polyp and medusa forms lacks cnidocytes a. Phylum Cnidaria, class Hydrozoa b. Phylum Cnidaria, class Scyphozoa c. Phylum Cnidaria, class Anthozoa d. Phylum Ctenophora 7 Explain the difference between the proximate cause of a behavior and the ultimate cause.

An unidentified animal is noted to possess the following characteristics: triploblastic eucoelomate body a cuticle that is shed via ecdysis To which of the following phyla does this organism belong? Group of answer choices A. Echinodermata B. Annelida C. Arthropoda D. Nematoda

Starfish Oral Side Describe the structures of the oral side of starfish. Such as peristome, ambulacral grooves, and tube feet.

(This is a book question, NONGRADED) List at least three features of squid that contribute to their sucess as predators.