Rhampotheca is

Options

A. Scaly skin of bird legs
B. Feathery tail of birds
C. Horny sheath covering the beak
D. Naked area covering the beak

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Ramphotheca":**
- The term "Ramphotheca" refers to a specific structure found in birds. It is derived from Greek, where "thicca" means covering.

2. **Identifying the Composition:**
- Ramphotheca is a horny sheath that covers the outer surface of a bird's beak. This sheath is made up of keratin, which is a protein that forms the outer layer of skin in many animals.

3. **Location of Ramphotheca:**
- The Ramphotheca is located on the outer surface of the beak, serving as a protective covering.

4. **Subdivisions of Ramphotheca:**
- The Ramphotheca is further divided into two distinct layers:
- **Rhinotheca:** This is the upper mandible's covering.
- **Nathotheca:** This is the covering of the lower mandible.

5. **Evaluating the Options:**
- Now, let's evaluate the options provided in the question:
- **Scaly skin of bird legs:** Incorrect, as this refers to the skin on the legs, not the beak.
- **Feathery tail of birds:** Incorrect, as this refers to the tail feathers, not the beak.
- **Horny sheath covering the beak:** Correct, as this accurately describes the Ramphotheca.
- **Naked area covering the beak:** Incorrect, as the Ramphotheca is not a naked area but a horny sheath.

6. **Conclusion:**
- Based on the definitions and evaluations, the correct answer is that Ramphotheca is the "horny sheath covering the beak."