The mode of the nutrition of bacteria is usually-

Options

A. Photo autotrophic
B. Chemo autotrophic
C. Heterotrophic and autotrophic
D. None

Answer

### Step-by-Step Solution

1. **Understanding Bacterial Nutrition**:
- Bacteria can obtain their nutrients in different ways. The primary modes of nutrition include autotrophic and heterotrophic.

2. **Defining Autotrophic Nutrition**:
- Autotrophic bacteria can produce their own food. This is similar to how green plants use sunlight to synthesize food through photosynthesis. Some bacteria possess chlorophyll and can perform photosynthesis, known as photoautotrophs.
- Example: Nostoc is a type of cyanobacteria that can perform photosynthesis.

3. **Defining Heterotrophic Nutrition**:
- Heterotrophic bacteria cannot produce their own food and rely on organic carbon sources for nutrition. They can be classified further into different categories such as parasites, saprophytes, or symbionts.
- Example: Clostridium is a genus of bacteria that is heterotrophic and requires organic matter for growth.

4. **Conclusion**:
- The mode of nutrition of bacteria is usually both autotrophic and heterotrophic. Therefore, the correct answer to the question is that bacteria can be heterotrophic and autotrophic.