Final answer:
The correct answer is a. Filtration, reabsorption, secretion, which are the three processes involved in the formation of urine and adjustment of blood composition in the kidneys.
Step-by-step explanation:
The formation of urine and the adjustment of blood composition involve three main processes: glomerular filtration, tubular reabsorption, and tubular secretion. These steps occur in the nephrons within the kidneys.
- Glomerular filtration happens in the glomerulus, where blood pressure forces water and solutes out of the blood and into the Bowman's capsule, starting the formation of urine.
- Tubular reabsorption is the process by which the renal tubules reabsorb water and valuable solutes from the filtrate back into the bloodstream, conserving important substances.
- Tubular secretion is the movement of substances from the blood into the renal tubules, where they are added to the urine filtrate, removing excess or harmful substances from the body.
These processes work together to filter the entire volume of blood through the kidneys about 300 times per day, ensuring waste products are excreted in the urine while maintaining the balance of fluids and electrolytes within the body.