What is the first event that occurs when a virus infects a host cell?

The first thing that virus does when it enters the host body is that it attaches to the cell membrane. When a new virion bud is produced wrapped up by the lipid bilayer of cell membrane, it contains all the proteins which were embedded in the lipid layer of the host cell.

Viral attachment with the membrane can be direct or in-direct which happens after it being swallowed into an endosome.

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.

i think its y= -4x-14