The most abundant solute in urine is _____.

• A. sodium chloride
• B. creatinine
• C. glucose
• D. urea

Answer: (D)

Verified step by step guidance

1. Understand the context of the question: The problem is asking about the most abundant solute in urine, which requires knowledge of human excretory physiology and the composition of urine.
2. Recall that urine is primarily composed of water, but it also contains various solutes that are waste products from metabolic processes. These solutes include urea, sodium chloride, creatinine, and glucose, among others.
3. Review the role of urea: Urea is a nitrogenous waste product formed during the breakdown of proteins and amino acids in the liver. It is highly soluble in water and is excreted in large quantities through urine to remove excess nitrogen from the body.
4. Compare the listed options: Sodium chloride is a salt that contributes to the osmolarity of urine but is not the most abundant solute. Creatinine is a waste product from muscle metabolism and is present in smaller amounts. Glucose is typically reabsorbed in the kidneys and is not abundant in normal urine unless there is a pathological condition like diabetes. Urea, on the other hand, is the most abundant solute in urine under normal conditions.
5. Conclude that the correct answer is urea based on its biological role and abundance in urine compared to the other options provided.