Molecules tend to move from an area where theybare more concentrated to an area where they are less conventrated. This process is called?

The process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated is called Diffusion :)

Hope this helps! please correct me if im wrong :)

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.