Nucleotide are composed of phosphate group, a sugar , and a nitrogenous base. DNA is made up of long strands of nucleotide. which part if the above molecule can differ between nucleotide? A. the sugar
B. the phosphate group
C. the nitrogen group
D. the sugar and phosphate group

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.

most community's take hundreds of years to become stable

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.