Final answer:
False. The amount of hormone in the blood does not have the biggest impact on urine volume.
Step-by-step explanation:
False. While the GFR (glomerular filtration rate) is an important factor in urine formation, the amount of hormone in the blood does not have the biggest impact on urine volume. The GFR determines the rate at which fluid is filtered from the blood in the glomerulus of the kidney.
The amount of hormone in the blood can affect the reabsorption of water in the renal tubules, but it is not the primary driver of urine volume. Hormones like ADH (antidiuretic hormone) and aldosterone play a role in adjusting the reabsorption of water and electrolytes to regulate urine volume and concentration.