Assertion: epidermis's cell | /r/CapableOf | undergo epiboly
Facets:
Source sentences:
text: Once convergent extension and radial intercalation are underway, the rest of the vegetal pole, which will become endoderm cells, is completely engulfed by the prospective ectoderm, as these top cells undergo epiboly, where the ectoderm cells divide in a way to form one layer.