Which of the following always produce an infectious spore like stage in their life cycles?

Options

A. Ciliated protozoans
B. Flagellated protozoans
C. Sporozoans
D. None

Answer

To determine which organisms always produce an infectious spore-like stage in their life cycles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking which group of organisms consistently produces a stage in their life cycle that is infectious and resembles a spore.

2. **Identify the Organism Groups**: The options provided include ciliated protozoans, flagellated protozoans, and sporozoans. We need to evaluate each group to see if they produce an infectious spore-like stage.

3. **Evaluate Ciliated Protozoans**: Ciliated protozoans, such as Paramecium, do not have a spore-like stage in their life cycle that is infectious. They reproduce asexually by binary fission and do not produce spores.

4. **Evaluate Flagellated Protozoans**: Flagellated protozoans, like Giardia, also do not produce a spore-like infectious stage. They reproduce through binary fission and do not have a lifecycle stage that is infectious in the form of spores.

5. **Evaluate Sporozoans**: Sporozoans, such as Plasmodium (the causative agent of malaria), are known for producing spore-like stages called sporozoites. These sporozoites are infectious and are transmitted through vectors (like mosquitoes) to host organisms.

6. **Conclusion**: Based on the evaluation, the group that always produces an infectious spore-like stage in their life cycle is the **Sporozoans**.

### Final Answer:
**Sporozoans** are the organisms that always produce an infectious spore-like stage in their life cycles.

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