This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urea cycle, Subject name: Biochemistry
In the biosynthesis of urea, one nitrogen atom is derived from ammonia while the other nitrogen atom is from: 
Select and explain. 
A. Glycine, B. Alanine, C. Aspaate, D. Glutamate
C: Aspaate
Answer: C: Aspaate 
Explanation: Nitrogens of urea are derived from:- N1 from ammonia N2 from Aspaate Source of urea Carbon and Nitrogen.