HEL PLSSS Which of the following describes the proper order of structures that an oxygen molecule diffuses through after entering the lungs?

Surfactant layer; alveolar space; capillary wall
Alveolar space; capillary wall; surfactant layer
Surfactant layer; capillary wall; alveolar space
Alveolar space; surfactant layer; capillary wall

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.

metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). the change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. i hoped i !