Mostly parasitic bacteria are

Options

A. Intracellular
B. Intercellular
C. Obligate
D. None

Answer

To answer the question "Mostly parasitic bacteria are," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Parasitic Bacteria**:
- Parasitic bacteria are organisms that depend on a host for survival. They derive nutrients from the host and can cause harm to it.

2. **Types of Parasitic Bacteria**:
- Parasitic bacteria can be classified based on their relationship with the host. They can be:
- **Intracellular**: These bacteria live inside the host cells.
- **Intercellular**: These bacteria live between the host cells.
- **Obligate**: These bacteria cannot survive outside the host and are completely dependent on it for their life cycle.

3. **Characteristics of Parasitic Bacteria**:
- Parasitic bacteria are often pathogens, meaning they can cause disease in the host.
- They cannot reproduce or survive outside the host cell, which makes them dependent on the host for their life processes.

4. **Analyzing the Options**:
- Given the definitions:
- **Intracellular** means living inside the cell.
- **Intercellular** means living between cells.
- **Obligate** refers to those that require a host for survival.
- Since parasitic bacteria rely on the host for nutrients and cannot live independently, they are primarily classified as **obligate intracellular parasites**.

5. **Conclusion**:
- Based on the characteristics and definitions, the correct answer to the question "Mostly parasitic bacteria are" is that they are **obligate intracellular parasites**.