Assertion: periosteum's cell | /r/HasProperty | absent
Facets:
Source sentences:
text: Mucus-secreting cells or glands are usually present in the epithelium but may be absent.
text: Mucus-secreting cells or glands are usually present in the epithelium but may be absent.
text: Mucus-secreting cells or glands are usually present in the epithelium but may be absent.