In his protista, Haeckel included

Options

A. Protozoa
B. Bacteria and fungi
C. Unicellular Algae
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding Haeckel's Classification**: Ernst Haeckel proposed a three-kingdom classification system in 1866. This system categorized living organisms into three main kingdoms: Animalia, Plantae, and Protista.

2. **Defining the Kingdom Protista**: In Haeckel's classification, the kingdom Protista was established to include a diverse group of organisms that do not fit neatly into the other two kingdoms (Animalia and Plantae).

3. **Identifying the Components of Protista**: The kingdom Protista includes various types of microorganisms. Specifically, it encompasses:
- **Protozoa**: Single-celled organisms that can be animal-like.
- **Bacteria**: Microscopic single-celled organisms that can be found in various environments.
- **Fungi**: While traditionally considered part of their own kingdom, Haeckel included some fungi-like organisms in Protista.
- **Unicellular Algae**: These are plant-like organisms that are typically photosynthetic and exist as single cells.

4. **Evaluating the Options**: Given the components of the kingdom Protista, we can evaluate the options provided in the question:
- **Option A**: Protozoa - Included in Protista.
- **Option B**: Bacteria and fungi - Bacteria are included, and some fungi-like organisms were also considered.
- **Option C**: Unicellular algae - Also included in Protista.
- **Option D**: All the above - This option encompasses all the previously mentioned groups.

5. **Conclusion**: Since all the mentioned groups (protozoa, bacteria, fungi, and unicellular algae) are included in Haeckel's kingdom Protista, the correct answer is **"all the above."**

**Final Answer**: All the above.

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