Beings from four phyla of the animal kingdom “breath” (do gas exchange) by diffusion. Which are those phyla? How is this type of respiration associated to features present in those animals?
The phyla of the animal kingdom whose beings do gas exchange by diffusion are the poriferans, the cnidarians, the platyelminthes (flatworms) and the nematodes (roundworms). This type of respiration in these beings is possible because their tissues and cells are relatively close to the exterior.
