The functional unit of the kidney is the:

**The reasoning** Think of your kidney as a factory with millions of tiny workers — each one is called a **nephron**. Just like a car factory has assembly lines that do the actual work, the nephron is the actual *structural and functional unit* that does the kidney's job: filtering blood, removing waste, and producing urine. Each kidney contains about 1 million nephrons. Each nephron has a glomerulus (tiny filter) and a tubule (reabsorption tube) working together to clean your blood 24/7. **Why the wrong options tempt you** - **Neuron** — This sounds similar to "nephron" (classic name trap!), but it's the functional unit of the *nervous system*, not the kidney. - **Alveolus** — This is the functional unit of the *lungs*, where gas exchange happens. - **Villus** — This is the functional unit of the *small intestine*, responsible for nutrient absorption. All these are functional units, just of *different organs*. JAMB loves testing if you can match the right unit to the right organ. **Quick takeaway** **Nephron = Kidney's worker.** Remember: "Neph" sounds like "kidney" in medical terms (nephrology = kidney doctor), so nephron belongs to the kidney!