Which one of the following statements is correct?

Urea is primarily produced in the liver through a series of biochemical reactions known as the urea cycle or ornithine cycle [6]. This metabolic pathway converts highly toxic ammonia, derived from the breakdown of excess amino acids, into urea, which is significantly less toxic [5]. Hepatocytes (liver cells) are the specific site for this synthesis, as they contain the necessary enzymes like arginase to facilitate the conversion [1]. While the kidneys are responsible for filtering urea from the blood and excreting it in the form of urine, they do not produce it [4]. The blood serves as a transport medium, carrying urea from the liver to the kidneys for removal [1]. Therefore, the liver is the exclusive site of urea synthesis in the human body [5].

Sources

1. [5] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > 5.5.1 Excretion in Human Beings > p. 96
2. [6] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > Artificial kidney (Hemodialysis) > p. 97
3. [2] https://en.wikipedia.org/wiki/Urea_cycle
4. [1] https://www.ncbi.nlm.nih.gov/books/NBK513323/
5. [4] https://www.fda.gov/media/168575/download