Choose the correct expression

Options

A. a group of related genera - Family
B. a group of related species - order
C. a group of related families - class
D. a group of related orders - genus

Answer

To solve the question "Choose the correct expression," we will analyze the options provided in the context of biological classification.

### Step-by-Step Solution:

1. **Understand Biological Classification**: Biological classification is a hierarchical system used to categorize living organisms. The hierarchy includes several ranks, starting from the broadest category (kingdom) to the most specific (species).

2. **Identify the Hierarchical Levels**: The main levels of biological classification are:
- Kingdom
- Phylum (or Division for plants)
- Class
- Order
- Family
- Genus
- Species

3. **Examine Each Option**:
- **Option A**: A group of related genera makes a family.
- This is correct. A family is indeed composed of related genera.
- **Option B**: A group of related species makes an order.
- This is incorrect. A group of related species makes a genus.
- **Option C**: A group of related families makes a class.
- This is incorrect. A group of related families makes an order.
- **Option D**: A group of related orders makes a genus.
- This is incorrect. A group of related orders makes a class.

4. **Conclusion**: Based on the analysis, the correct expression is **Option A**: "A group of related genera makes a family."

### Final Answer:
The correct expression is **Option A**: A group of related genera makes a family.