Which class of Protozoa includes all parasitic forms ?

Options

A. Mastigophora
B. Ciliata
C. Sporozoa
D. parasites

Answer

To answer the question "Which class of Protozoa includes all parasitic forms?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand Protozoa**: Protozoa are single-celled eukaryotic organisms. They can be classified into different classes based on their characteristics and modes of life.

2. **Identify the Classes**: The question provides four options:
- Option 1: Mastigophora
- Option 2: Ciliata
- Option 3: Sporozoa
- Option 4: Parasites

3. **Define Parasitic Forms**: Parasitic protozoa are those that live on or in a host organism and derive nutrients at the host's expense. They cannot live independently.

4. **Analyze Each Option**:
- **Mastigophora**: This class includes protozoa that have flagella. While some are parasitic, many are free-living, so this option is incorrect.
- **Ciliata**: This class has protozoa covered with cilia. Similar to Mastigophora, it includes both free-living and some parasitic forms, making this option incorrect as well.
- **Sporozoa**: This class is known for including obligate intracellular parasites. They reproduce by forming spores and are entirely parasitic, making this the correct option.
- **Parasites**: This term refers to organisms that live in or on a host. However, it is not a class of protozoa, so this option is incorrect.

5. **Conclusion**: Based on the analysis, the class of Protozoa that includes all parasitic forms is **Sporozoa**.

### Final Answer:
The class of Protozoa that includes all parasitic forms is **Sporozoa**.

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