Characteristics of epithelial tissues may include

Options

A. absorption
B. secretion
C. protection
D. all of the above.

Explanation

### Step-by-Step Solution:

1. **Understanding Epithelial Tissues**: Epithelial tissues are a group of cells that line the surfaces of organs and structures throughout the body. They serve various functions including protection, absorption, and secretion.

2. **Analyzing the First Option - Absorption**:
- Epithelial tissues, particularly in the intestines, have microvilli (tiny finger-like projections) that increase the surface area for absorption. This allows for efficient uptake of nutrients from digested food.
- **Conclusion**: This option is correct.

3. **Analyzing the Second Option - Secretion**:
- Epithelial cells are responsible for the secretion of various substances. For example, in the stomach and intestines, they secrete digestive juices and enzymes that aid in digestion.
- **Conclusion**: This option is also correct.

4. **Analyzing the Third Option - Protection**:
- Epithelial tissues provide a protective barrier against mechanical injury, pathogens, and chemical exposure. They line organs such as the stomach and respiratory system, helping to protect underlying tissues.
- **Conclusion**: This option is correct as well.

5. **Analyzing the Fourth Option - All of the Above**:
- Since all the previous options (absorption, secretion, and protection) are correct, this option, which states "all of the above," must also be correct.
- **Conclusion**: The correct answer is option four, as it encompasses all the characteristics mentioned.

### Final Answer:
The characteristics of epithelial tissues may include absorption, secretion, and protection. Therefore, the correct answer is "all of the above."

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