Differentiation of multipotent neural crest cells requires: a) Convergent extension of neural crest to position the cells in the proper location. b) Proper anterior/posterior patterning of the neural crest by retinoic acid and Fgf8. c) Migration of neural crest cells to expose them to different signals. d) Establishment of a morphogen gradient in the neural plate?
1) Convergent extension of neural crest to position the cells in the proper location
2) Proper anterior/posterior patterning of the neural crest by retinoic acid and Fgf8
3) Migration of neural crest cells to expose them to different signals
4) Establishment of a morphogen gradient in the neural plate