<prompt> The two nitrogen atoms that are incorporated into the urea cycle. The source of the nitrogen isGlutamate AspaateAspaate ArginineAspaate NH3Glutamate NH3  <response>: Two nitrogen atoms of urea are derived from two different sources, one from ammonia and the other directly from alpha amino group of aspaic acid.Ref: DM Vasudevan - Textbook of Biochemistry, 6th edition, page no: 203 