<prompt> Facial development takes place bw:4-8 week8-l0week12-14week18-20week  <response>: Ans. a. 4-8 week Development of faceFacial development occurs mainly between 4th and 8th weeks, and is induced by migration of cells of neural crest.Five facial primordia appear as prominences of mesenchyme : a frontonasal process, a pair of maxillary processes and a pair of mandibular processes. 