Which of the following used diffusion as the principal method of gaseous exchange?

The earthworm uses diffusion as the principal method of gaseous exchange. Earthworms are terrestrial invertebrates that breathe through their skin, which is thin, moist, and permeable to gases. As they move through the soil, oxygen from the air diffuses through their skin and into their bloodstream, while carbon dioxide and other waste gases diffuse out of their bodies and into the surrounding environment. This process of gas exchange is called diffusion, which is the passive movement of gases from an area of high concentration to an area of low concentration. Therefore, the earthworm is the organism that uses diffusion as the principal method of gaseous exchange.