Define and compare four level of protein organization.

Explanation:

There are four levels of protein structure: primary, secondary, tertiary, and quaternary. These levels also reflect their temporal sequence. Proteins are synthesized as a primary sequence and then fold into secondary → tertiary → and quaternary structures.

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.