Waste product of mammal is -

Options

A. Ammonia
B. Urea
C. Uric acid
D. Guanine

Answer

**Step-by-Step Solution:**

1. **Understanding Waste Products in Animals:**
- Animals produce waste products as a result of metabolic processes. The main nitrogenous waste products include ammonia, urea, uric acid, and guanine.

2. **Identifying the Waste Product of Mammals:**
- Among the options provided (ammonia, urea, uric acid, guanine), we need to identify which one is primarily excreted by mammals.

3. **Definition of Ureotelic Animals:**
- Mammals, along with many terrestrial amphibians and some marine fishes, are classified as ureotelic animals. This means they primarily excrete urea as their nitrogenous waste.

4. **Metabolism of Ammonia:**
- Ammonia is a toxic byproduct of protein metabolism. In mammals, ammonia is converted into urea in the liver to reduce toxicity.

5. **Excretion Process:**
- Once urea is formed in the liver, it is released into the bloodstream. The kidneys filter the blood, allowing urea to be excreted from the body through urine.

6. **Comparison with Other Waste Products:**
- Ammonia is typically excreted by aquatic animals like bony fishes. Uric acid is the primary waste product of birds and reptiles. Guanine is a nitrogenous base and not a waste product in the context of excretion.

7. **Conclusion:**
- Therefore, the correct answer to the question "Waste product of mammals is -" is **urea**.

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