Bacteria that are saprotrophs but can be a parasite and cause disease upon introduction to host body are called as

Options

A. Obligate saprotroph
B. Obligate parasite
C. Facultative parasite
D. Facultative saprotroph

Answer

To solve the question regarding the classification of bacteria that are saprotrophs but can act as parasites and cause disease upon entering a host body, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Saprotrophs**: Organisms that obtain nutrients by decomposing dead organic matter.
- **Parasites**: Organisms that live on or in a host and obtain nutrients at the host's expense, often causing harm.

2. **Analyze the Options**:
- **Obligate Saprotrophs**: These organisms strictly depend on dead matter for nutrition and cannot switch to parasitic behavior. Thus, they cannot cause disease in a host.
- **Obligate Parasites**: These organisms strictly rely on a host for nutrition and cannot switch to saprotrophic behavior. They also cannot be saprotrophs.
- **Facultative Parasites**: These organisms can switch between being a parasite and a saprotroph, but they primarily act as parasites.
- **Facultative Saprotrophs**: These organisms primarily act as saprotrophs but can switch to a parasitic mode when introduced to a host body.

3. **Identify the Correct Answer**:
- Since the question specifically asks for bacteria that are primarily saprotrophs but can also act as parasites, the correct answer is **Facultative Saprotrophs**. They can switch from saprotrophic nutrition to parasitic nutrition when necessary.

### Final Answer:
**Facultative Saprotrophs**

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