Final answer:
The formula represents the overall balance of filtration, reabsorption, and secretion in the kidney during the process of excretion.
Step-by-step explanation:
The formula "Amount of substance excreted = amount filtered — amount reabsorbed+ amount secreted" relates to the process of excretion in the kidney. In the kidney, substances are filtered from the blood, reabsorbed back into the blood, and secreted into the urine. The formula represents the overall balance of these processes and helps in understanding how the kidney regulates the composition of urine and maintains homeostasis in the body.