71) Animals that do not have a backbone called ________.
72) : 1380900.
71) Animals that do not have a backbone are called ________.
72) Sponges acquire food by ________ as water passes through.
73) The structure in cnidarians with both digestive and circulation functions is the ________.
74) The features common to all chordates are: ________, ________, ________, and ________.
75) What are the benefits and challenges of an exoskeleton?
76) The animal phyla with the most diversity and greatest representation in the animal kingdom have developed tissues, organs, and body cavities. Less successful phyla have not. Evaluate and explain why this is so.
71) Animals that do not have a backbone called ________.
72) : 1380900
