AIntroFIG 2: Scanning electron micrographs (SEMs) of young and old C. elegans.

Panels show nemtodes of different ages with anterior on left and posterior on right.
A. In a young adult (2-day), the external cuticle appears mostly smooth.
B. 7-day-old nematode features more distinctive annuli in head and tail with some deeper wrinkles in these areas. Vulval extrusion is visible in this example.
C. 13-day-old nematode has extensive wrinkling along entire body with deep grooves and cuticular folds that deform the shape of the body structure with a large vulval extrusion in this example.
(Image source: A. Ghazi.)

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