Option 1: Urea

Urea is a waste product formed in the liver as a result of the breakdown of proteins. It is filtered by the kidneys and excreted out of the body through urine. Therefore, urea is excreted in urine under normal circumstances.

Option 2: Sodium

Sodium is an essential electrolyte involved in various bodily functions. It is regulated by the kidneys, and excess sodium is excreted through urine. However, in normal circumstances, the majority of sodium is reabsorbed by the kidneys to maintain the body`s electrolyte balance. So, although a small amount of sodium is excreted in urine, it is not completely eliminated.

Option 3: Amino Acid (Correct Answer)

Amino acids are the building blocks of proteins, and they are essential for various physiological processes in the body. Normally, amino acids are actively reabsorbed by the kidneys to prevent their loss. Therefore, under normal circumstances, amino acids are not excreted in urine in any significant amounts.

Option 4: Potassium

Potassium is an important electrolyte involved in nerve and muscle function. It is regulated by the kidneys, and excess potassium is excreted through urine. However, similar to sodium,