Q: You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
The Urea (or the Krebs-Hensliet) cycle outlines the mechanism by which ammonia is finally produced in the final reaction (involving Arginine, if I am right)\n\nAmmonia excretion can also be regarded as excretion of Nitrogen from different intermediates in the body. All of these N containing intermediates converge into the TCA cycle from where they become amino acids through enzymes known as deaminases or transminases. These amino acids converge to a common amino acid (alanine in humans, if i recollect well) which then travels to Kidney and initiates the UREA cycle to finally result in the production of Ammonia
A:
the main substrate for the secretion of ammonia in the kidney?