The document describes the early stages of embryonic development in 3 sentences or less. It discusses the formation of the proamnion, area opaca, area pellucida, Hensen's node, primitive pit, primitive groove, primitive ridge, anterior neuropore, neural groove, neural fold, head fold, somites, and unsegmented mesoderm during embryogenesis.

1. 3
2
1 – Head Process
2 – Head Fold
1 3 – Proamnion
5 4 – Area Opaca
4 5 – Area Pellucida

2. Hensen’s Node
Primitive Pit
Primitive Groove
Primitive Ridge
Area Pellucida

3. Anterior Neuropore
Head Fold
Neural Groove
Neural Fold
Head fold
Somites
Unsegmented Mesoderm
Hensen’s Node