In the basis of decreasing toxicity , which sequence of excretory waste is correct ?

Options

A. Urea `gt` Uric acid `gt` Ammonia `gt` Amina acid
B. Ammonia `gt` Urea `gt` Uric acid `gt` Amino acid
C. Ammonia `gt` Uric acid `gt` Urea `gt` Amino acid
D. Urea `gt` Ammonia `gt` Amino acid `gt` Uric acid

Answer

To determine the correct sequence of excretory waste based on decreasing toxicity, we need to analyze the nitrogenous wastes produced in organisms. Here’s a step-by-step solution:

### Step 1: Identify the nitrogenous wastes
The primary nitrogenous wastes produced by organisms include:
- Ammonia
- Urea
- Uric Acid

### Step 2: Understand the toxicity of each waste
- **Ammonia**: This is the most toxic form of nitrogenous waste. It is produced directly from the deamination of amino acids and requires a large amount of water to be safely excreted.
- **Urea**: This is less toxic than ammonia. It is produced in the liver through the urea cycle, which converts ammonia into urea, allowing for safer excretion with less water.
- **Uric Acid**: This is the least toxic of the three. It is a more complex molecule and can be excreted with minimal water loss, making it advantageous for organisms in arid environments.

### Step 3: Arrange the wastes in order of decreasing toxicity
Based on the toxicity levels:
1. Ammonia (most toxic)
2. Urea (moderately toxic)
3. Uric Acid (least toxic)

### Final Sequence
Thus, the correct sequence of excretory waste in terms of decreasing toxicity is:
**Ammonia > Urea > Uric Acid**