Describe the role of liver, lungs and skin in excretion.

Explanation

### Step-by-Step Text Solution

**1. Role of the Liver in Excretion:**
- The liver is the largest gland in the human body and plays a crucial role in the excretion process.
- It converts decomposed hemoglobin from old red blood cells into bile pigments, specifically bilirubin and biliverdin.
- The liver also excretes cholesterol, steroid hormones, vitamins, drugs, and other waste materials through bile.
- Additionally, the liver is responsible for the formation of urea. Ammonia, which is toxic, is converted into urea, which is then eliminated from the body through urine.

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