The spontaneous movement of gases across a permeable membrane takes place by ______________.

spontaneous (occurring naturally) movement of gases across a permeable membrane from a region of high concentration to the region of low concentration is known as diffusion.e.g. Carbon dioxide (CO₂) (Which is a cellular waste required to be excreted out by the cell) accumulates in high concentrations inside the cell. In the cell's external environment, the concentration of carbon dioxide (CO₂) is low as compared to that inside the cell. As soon as there is difference in concentration of CO₂ inside and outside a cell, CO₂ moves out of the cell from a region of high concentration to a region of low concentration outside the cell by the process of diffusion. Similarly oxygen (O₂) enters the cell by the process of diffusion when the level or concentration of oxygen inside the cell decreases.