Explain why and how the polar covalent bonds found in water molecules are responsible for water's ability to dissolve many substances, particularly
ionic compounds such as salt.

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.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )

that is wrong, its not thymus.

the food storage products of chrysophytes are oils or the polysaccharide laminarin.   formerly classified as plants, the chrysophytes contain the photosynthetic pigments chlorophyll a and c all but the yellow-green algae also contain the carotenoid pigment fucoxanthin.