The largest amounts of nitrogen is excreted from a mammalian body by

Options

A. Breath
B. Sweat
C. Urine
D. Faeces

Answer

To answer the question, "The largest amounts of nitrogen is excreted from a mammalian body by," we can follow these steps:

### Step 1: Understand Nitrogen Excretion
Mammals excrete nitrogen in various forms, primarily through metabolic waste. The main forms of nitrogenous waste include ammonia, urea, and uric acid.

### Step 2: Identify the Main Nitrogenous Waste in Mammals
In mammals, the predominant form of nitrogenous waste is urea. Urea is produced in the liver through the urea cycle and is less toxic than ammonia, making it a suitable form for excretion.

### Step 3: Analyze the Excretion Process
Urea is primarily excreted through urine. The kidneys filter the blood, removing excess urea and other waste products, which are then expelled from the body in urine.

### Step 4: Compare Other Forms of Nitrogen Excretion
While ammonia can be excreted, it is primarily in aquatic organisms due to its high toxicity. Uric acid is excreted by birds and reptiles, but it is not the primary form of nitrogen waste in mammals.

### Step 5: Conclusion
Given that urea is the main nitrogenous waste product excreted by mammals, the answer to the question is that the largest amounts of nitrogen are excreted from a mammalian body by urea.

### Final Answer
The largest amounts of nitrogen are excreted from a mammalian body by **urea**.

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