What does the interneuron do between the afferent and efferent neurons?

Interneurons enable the communication between afferent and efferent neurons.  

Explanation:

Internerons are also known as relay neuron. These neurons are classified into local neuron and relay neuron. Interneurons are involved in the process of reflex action and neurogenesis.

Interneurons are known to create neural circuits between the afferent and efferent neuron. This circuit helps in communication and transfer the information between afferent and efferent neurons.

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.