3. in the phylum porifera, the highest level of organization is arguably only at the cellular' levél. how
have the cnidarians become more complex in terms of organization? what does this mean?

Cnidarians have become more complex in terms of organisation than the poriferan as they have developed a tissue level organisation,they show locomotion , exhibit polymorphism  and a radial symmetry.

This means that cnidarians evolved later than poriferans and are adapted to more competitive and complex environment.

Explanation:

Poriferans are pore bearing animals , they have cell specialization but no tissue level organisation while cnidarians are diploblastic and exhibit tissue level organisation.Poriferans are asymmetrical organisms hence are primitive to the radially symmetrical cnidarians.poriferans obtain nutrition mostly through filter feed while cnidarians have a gastro vascular cavity for digestion.

Ithink the dna sequences may vary but the amino acid sequences are identical. 

The answer is a. i hope this