During the Precambrian time the oceans and atmosphere formed around Earth and the concentration of oxygen gas eventually reach the point where it could support a aerobic

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.

it's unlikely a majority of a large population would agree on issues

hope this : )

energy and particles