Which of the following kingdoms includes unicellular eukaryotes?

Options

A. Monera
B. Fungi
C. Protista
D. Plantae

Explanation

To determine which kingdom includes unicellular eukaryotes, we can analyze each of the provided options step by step.

### Step 1: Analyze the Kingdom Monera
- **Monera** is known to include all types of unicellular prokaryotes, such as bacteria.
- Since prokaryotes are not eukaryotes, Monera does not include unicellular eukaryotes.

**Hint:** Remember that prokaryotes lack a defined nucleus, which distinguishes them from eukaryotes.

### Step 2: Analyze the Kingdom Fungi
- **Fungi** primarily consists of multicellular organisms, but it does include yeast, which is a unicellular eukaryote.
- However, since not all fungi are unicellular (most are multicellular), this option cannot be considered the best answer for the question.

**Hint:** Consider whether the kingdom primarily consists of unicellular or multicellular organisms.

### Step 3: Analyze the Kingdom Protista
- **Protista** is a diverse kingdom that includes primarily unicellular eukaryotes.
- Examples of unicellular eukaryotes in this kingdom include protozoa and certain types of algae.
- This makes Protista the correct answer for the question.

**Hint:** Look for kingdoms that are known for their diversity in unicellular organisms.

### Step 4: Analyze the Kingdom Plantae
- **Plantae** consists mainly of multicellular eukaryotic organisms, specifically plants.
- Since Plantae does not include unicellular organisms, this option is incorrect.

**Hint:** Recall that Plantae is associated with multicellular organisms that perform photosynthesis.

### Conclusion
After analyzing all the options, the kingdom that includes unicellular eukaryotes is **Protista**.

**Final Answer:** The correct answer is **Option 3: Protista**.