Choose the correct statement with respect to unicellular organisms:

Options

A. in unicellular organisms, tissues work in co-ordination to perform different functions.
B. unicellular organisms do not require food.
C. unicellular organisms respire and reproduce.
D. all unicellular organisms move by cilia.

Explanation

To solve the question "Choose the correct statement with respect to unicellular organisms," we will analyze each statement provided in the options.

### Step-by-Step Solution:

1. **Understanding Unicellular Organisms**:
- Unicellular organisms are those that consist of a single cell. Examples include bacteria, amoeba, and paramecium.

2. **Evaluating the Statements**:
- **Statement 1**: "In unicellular organisms, tissues work in coordination to perform different functions."
- This statement is **incorrect**. Unicellular organisms do not have tissues; they perform all necessary functions within a single cell.

- **Statement 2**: "Unicellular organisms do not require food."
- This statement is **incorrect**. All organisms, including unicellular ones, require food for energy and survival.

- **Statement 3**: "Unicellular organisms respire and reproduce."
- This statement is **correct**. Unicellular organisms carry out essential life processes such as respiration and reproduction, despite being made of only one cell.

- **Statement 4**: "All unicellular organisms move by cilia."
- This statement is **incorrect**. While some unicellular organisms do move using cilia, others may use flagella or pseudopodia for movement.

3. **Conclusion**:
- The correct statement regarding unicellular organisms is **Statement 3**: "Unicellular organisms respire and reproduce."

### Final Answer:
The correct statement with respect to unicellular organisms is: **"Unicellular organisms respire and reproduce."**