Animals in the same phylum may have different nervous system structures. for example, octopuses have large, complex brains while clams have a simple network

The correct answer will be- ring-like network

Explanation:

Both Octopus and Clams (Bivalves) belongs to the same phylum called Mollusks but different classes.  Although both are molluscs they show variations in their external as well as internal structures.

The case of their nervous system is an example of the nervous system as the nervous system of clams is very simple and consists of ganglia which form a ring-like structure around their oesophagus whereas the nervous system of octopus is very complex just like invertebrates.

Thus, ring-like a network is the correct answer.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

there is no stairs in bungalow

explanation:

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