Name the main excretory organs of humans.

Answer

### Step-by-Step Solution:

1. **Identify the Main Excretory Organs**: The primary excretory organs in humans are the kidneys. They play a crucial role in filtering blood and producing urine.

2. **Understanding the Function of Kidneys**: The kidneys are responsible for excreting urea, which is a less toxic form of nitrogenous waste. This waste is produced from the metabolism of proteins.

3. **Role of Nephrons**: Within the kidneys, the functional units called nephrons are responsible for the filtration process. Each kidney contains about a million nephrons that filter blood and form urine.

4. **Urine Transport**: After urine is formed in the kidneys, it is transported through a pair of tubes called ureters. The ureters carry urine from the kidneys to the urinary bladder.

5. **Storage and Excretion**: The urinary bladder stores urine until it is ready to be excreted. Once full, urine is expelled from the body through the urethra.

6. **Summarizing the Components**: The main excretory organs in humans include:
- **Kidneys**: Main organs for filtration and urine production.
- **Ureters**: Tubes that transport urine from kidneys to the bladder.
- **Urinary Bladder**: Storage organ for urine.
- **Urethra**: Tube through which urine is expelled from the body.

### Final Answer:
The main excretory organs of humans are the **kidneys**, **ureters**, **urinary bladder**, and **urethra**.

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