The condition of having a single flagellum at one end of a bacterium is
(a) Peritrichous
(b) Amphitrichous
(c) Lophotrichous
(d) Monotrichous

Options

A. Peritrichous
B. Amphitrichous
C. Lophotrichous
D. Monotrichous.

Answer

To solve the question regarding the condition of having a single flagellum at one end of a bacterium, we will analyze the options provided and identify the correct term.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the specific term that describes a bacterium with a single flagellum located at one end.

2. **Review the Options**:
- (a) Peritrichous: This term refers to bacteria that have flagella distributed all around their surface.
- (b) Amphitrichous: This term describes bacteria that have flagella at both ends.
- (c) Lophotrichous: This term refers to bacteria that have a tuft or bundle of flagella at one end.
- (d) Monotrichous: This term describes bacteria that have a single flagellum at one end.

3. **Identify the Correct Option**:
- Based on the definitions:
- Peritrichous is not correct because it describes flagella all over the surface.
- Amphitrichous is not correct because it describes flagella at both ends.
- Lophotrichous is not correct because it describes a bundle of flagella at one end.
- Monotrichous is correct because it specifically refers to a single flagellum at one end.

4. **Conclusion**: The correct answer to the question is (d) Monotrichous.

### Final Answer:
(d) Monotrichous

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