The cell membrane and the associated transport proteins found in the membrane are responsible for regulating the movement of hundreds, if not thousands, of different types of molecules into and out of the cell.
Among the gases emitted when fossil fuels are burned, one of the most significant is carbon dioxide, a gas that traps heat in the earth's atmosphere. Over the last 150 years, burning fossil fuels has resulted in more than a 25 percent increase in the amount of carbon dioxide in our atmosphere.
Fossil fuels are natural resources such as coal, oil (including gasoline and diesel fuel) and natural gas. They are formed from the remains of ancient plant and animal life. Fossil fuel burning powers our vehicles and industries, heats and cools our buildings, and runs appliances.