Protozoans are not included in kingdom Animalia because-

Options

A. Mostly asymmetrical
B. Unicellular eukaryotes
C. Heterotrophic nature
D. Multicellular prokaryotes

Answer

**Step-by-Step Solution:**

1. **Understanding Protozoans**: Protozoans are a diverse group of unicellular organisms that are classified under the kingdom Protista. They are eukaryotic, meaning their cells contain a nucleus and other organelles.

2. **Characteristics of Kingdom Animalia**: The kingdom Animalia consists of multicellular organisms that are also eukaryotic. Members of this kingdom are typically heterotrophic, meaning they obtain their food by consuming other organisms.

3. **Unicellularity vs. Multicellularity**: One of the primary reasons protozoans are not included in the kingdom Animalia is that they are unicellular. In contrast, all members of the Animalia kingdom are multicellular.

4. **Photosynthesis in Some Protozoans**: Some protozoans possess chloroplasts and can perform photosynthesis. This characteristic is not typical of the members of the kingdom Animalia, which do not have the ability to photosynthesize.

5. **Conclusion**: Therefore, protozoans are classified in the kingdom Protista due to their unicellular structure, eukaryotic nature, and in some cases, their ability to perform photosynthesis, which distinguishes them from the multicellular organisms of the kingdom Animalia.

**Final Answer**: Protozoans are not included in kingdom Animalia because they are unicellular organisms, whereas all members of kingdom Animalia are multicellular. Additionally, some protozoans can perform photosynthesis, which is not a characteristic of animals.

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