Fig. 3. (A) Low-magnification electron micrograph of lung tissue from Macropus eugenii at birth. Scale bar, 5 µm. (B) Enlargement of the airspace region highlighted in black in A, showing the distribution of SP-B associated with extracellular surfactant. Immunogold particles are indicated by arrows. Scale bar, 0.5 µm. (C) Enlargement of the cell region highlighted in white in A, showing the distribution of SP-B within the cytoplasm and lamellar bodies. Immunogold particles are indicated by arrows. Scale bar, 0.5 µm.