Final answer:
The most abundant waste solute in urine is urea, which is a by-product of protein catabolism and is excreted by the kidneys as part of the body's waste management and homeostasis.
Step-by-step explanation:
The most abundant waste solute in urine is urea. Urea is a by-product of protein catabolism and is more soluble than uric acid, making it a major constituent of urine. The kidneys play a vital role in filtering out waste products from the blood, and one of their main functions is the excretion of waste products produced by metabolism, including nitrogenous wastes such as urea and uric acid.
Uric acid is also a waste product, but it is mainly filtrate from blood by the kidneys and excreted in smaller quantities compared to urea. The urinary system works to maintain homeostasis by eliminating excess water, electrolytes, and metabolic wastes such as urea.