Plz why might uranus and neptune have proportionally less elemental hydrogen in their atmosphere than their more massive companions, jupiter and saturn? hint: hydrogen is the lightest element.

they are farther from the sun and most of their atmosphere is nitrogen and methane and the are smaller and have a denser core than both saturn and juipter

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.

telophase and anaphase