Assertion: uterus's layer | /r/CapableOf | thicken in preparation
Facets:
value: for an embryo
type: PURPOSE
value: each month
type: TEMPORAL
Source sentences:
text: The innermost layer of the uterus — the endometrium — thickens each month in preparation for an embryo, but is shed in the following menstrual period if fertilization does not occur.