Assertion: epithelium's layer | /r/CapableOf | serve as outer layer
Facets:
value: for some structure
type: PURPOSE
value: always
type: TEMPORAL
Source sentences:
text: A layer of epithelial layer always serves as an outer layer for some structure, but, when looking at a tissue preparation on a slide, do not assume that just because you have found one end of the tissue sample you are automatically looking at epithelial tissue.