Decay by bacteria is

Options

A. aerbic breakdown of any organic matter
B. aerobic breakdown of inorganic matter
C. anaerobic breakdown of organic matter with foul odour
D. aerobic breakdown of proteins.

Answer

To answer the question "Decay by bacteria is:", we need to analyze the provided options and understand the processes involved in bacterial decay.

### Step-by-Step Solution:

1. **Understanding Bacterial Decay**:
- Bacteria play a crucial role in the decomposition of organic matter. This process can occur in the presence of oxygen (aerobic) or in its absence (anaerobic).

2. **Evaluating the Options**:
- **Option 1**: Aerobic breakdown of any organic matter.
- This option is incorrect because while bacteria can decompose organic matter aerobically, the term "any" is too broad. Not all organic matter is decomposed in the same way.

- **Option 2**: Aerobic breakdown of inorganic matter.
- This option is incorrect as bacteria do not decompose inorganic matter. They are primarily involved in the breakdown of organic substances.

- **Option 3**: Anaerobic breakdown of organic matter with foul odor.
- This option is correct. Anaerobic decomposition occurs without oxygen and is typically slower, producing foul odors due to the byproducts of the breakdown process.

- **Option 4**: Aerobic breakdown of proteins.
- This option is incorrect because while bacteria can decompose proteins aerobically, the statement is too specific and does not encompass the broader process of decay by bacteria.

3. **Conclusion**:
- The correct answer to the question "Decay by bacteria is" would be **"anaerobic breakdown of organic matter with foul odor."**

### Final Answer:
Decay by bacteria is **anaerobic breakdown of organic matter with foul odor.**

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