A researcher is testing a new antiviral agent that reduces the severity of a highly contagious strain of the flu virus. She has found that the antiviral agent only it administered within 48 hours of the onset of symptoms. This information would lead the researcher to believe the virus

virus is at its infant stage for the first 2days and develop into adulthood afterwards hence the virus becomes resistant to the antiviral agent.

Explanation:

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.