Task: Class Definition Understanding (ontology: Earth_Environment/EnvironmentOntology)

Which of the following definitions best describes 'primordium'?

A. the concept are populations of contiguous cells that are morphologically distinct and already correspond in extent to a later organ/tissue[FBbt, Hartenstein, V. (2004)].
B. The the concept is the primordial vasculature that will develop into blood vessels by the process of tubulogenesis[GO]. The the concept is composed of angioblast or vascular endothelial cells in a solid linear mass called a cord. The cord then undergoes tubulogenesis to form the lumen of the vessels[ZFA].
C. A portion of tissue that will develop into vasculature.
D. An the concept is a thickening of the ectoderm that is the primordium of many structures derived from the ectoderm[GO].

Answer: the concept are populations of contiguous cells that are morphologically distinct and already correspond in extent to a later organ/tissue[FBbt, Hartenstein, V. (2004)].