Assertion: eye | /r/MadeOf | just one photoreceptor
Facets:
Source sentences:
text: The simplest eyes, then, may consist of just one photoreceptor and one pigment cell or even a single cell that includes both photo- and shading pigments as found in some flatworms and algae (e.g., Arendt and Wittbrodt 2001; Oakley 2003).