gills
The gas occurs by simple diffusion through the cells.
the alveolus
in the leave
gas exchange occurs between the thin walls of the alveoli and the thin walls of the capillaries
in their gills.
In the alveoli
lungs
Gas exchange does not occur in the pleura. The pleura is a membrane that lines the outside of the lungs and inside of the chest cavity. Gas exchange, where oxygen is taken in and carbon dioxide is removed, happens in the alveoli of the lungs.
Capillaries
Between the avioli and the lungs.
Sponges conduct gas exchange primarily through a process known as diffusion. They have a porous body structure that allows water to flow through their canals, where oxygen dissolved in the water diffuses into the sponge cells, while carbon dioxide produced by cellular respiration diffuses out into the water. This efficient system relies on the constant movement of water, facilitated by specialized cells called choanocytes, which create water currents. Consequently, sponges do not require specialized respiratory organs, as their simple body plan supports direct gas exchange with the surrounding environment.
Gaseous exchange takes place when the volume of the chest cavity is increased or decreased.