A number of organic compounds can be decomposed by

Options

A. Pseudomonas
B. Mycoplasma
C. Chemolithotrophs
D. Azotobacter.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which organism is capable of decomposing a number of organic compounds. Organic compounds typically include plant and animal residues found in soil.

2. **Analyzing the Options**:
- **Option 1: Pseudomonas** - This is a type of bacteria known for its ability to decompose organic matter in the soil, releasing carbon dioxide, energy, water, and essential nutrients.
- **Option 2: Mycoplasma** - This is the smallest prokaryote and lacks a cell wall. It does not play a role in decomposing organic compounds.
- **Option 3: Chemolithotrophs** - These are microbes that obtain energy by oxidizing inorganic compounds, not organic ones, making them unsuitable for this question.
- **Option 4: Azotobacter** - This is a free-living aerobic nitrogen-fixing bacterium, which does not primarily decompose organic compounds.

3. **Identifying the Correct Answer**: Based on the analysis, Pseudomonas is the only organism among the options that is known for decomposing organic compounds effectively.

4. **Conclusion**: The correct answer to the question is **Option 1: Pseudomonas**.