Which list shows three components of an organ system in order of least complex to most complex? red blood cell, heart, tissue.
skeleton, bone, bone cell.
muscle cell, muscle tissue, stomach.
lung tissue, lung, circulatory system.

I believe its muscle cell, muscle tissue, stomach

Explanation:

The order for organ systems from least complex to most complex is: Cell, tissue, organ, organ system. Hope this helps

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.