Snake ciliated lung cells and mucus. Coloured scanning electron micrograph (SEM) of ciliated cells (green) and mucus (pink) in the lung of a snake. The tubular bodies of snakes require all of their organs to be long and thin. In most species, only one lung is functional. This sample is from the lung bronchioles. Magnification: x4000 when printed at 10 centimetres high.
