pnas_figure1

Dramatic changes occur in the geometry of the developing lungs after birth. Images of 4 days old (left), 21 days old (middle), and adult (right) rat lungs, taken by light microscopy (upper row) and by scanning electron microscopy (lower row). Original source: Fig. 1 of Proc. Natl. Acad. Sci.USA. 109(13):5092-5097, 2012. Copyright: PNAS