Subrostral fossae are

Options

A. Three terminal over upper jaw
B. Three terminal over lower jaw
C. Two lateral over upper jaw
D. Two lateral over lower jaw

Answer

### Step-by-Step Solution

1. **Understanding the Term "Subrostral Fossae":**
- The term "subrostral fossae" refers to specific anatomical structures found in frogs. The word "fossa" means a depression or a hollow area.

2. **Identifying the Location:**
- Subrostral fossae are located in the mouth of the frog, specifically on the upper jaw.

3. **Counting the Fossae:**
- There are three subrostral fossae present on the upper jaw of the frog.

4. **Differentiating from Other Structures:**
- It is important to differentiate subrostral fossae from other structures in the frog's mouth, such as the prelingual elevations, which are three elevations located on the lower jaw.

5. **Function of Subrostral Fossae:**
- The primary function of the subrostral fossae is to assist in the closure of the mouth during gas exchange, preventing any intermixing of gases.

6. **Choosing the Correct Option:**
- Given the options provided:
- 3 terminal over upper jaw (correct)
- 3 terminal over lower jaw (incorrect)
- 2 lateral over upper jaw (incorrect)
- 2 lateral over lower jaw (incorrect)
- The correct answer is that subrostral fossae are "3 terminal over upper jaw."

### Final Answer:
Subrostral fossae are **3 terminal over upper jaw**.

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