In frogs, testes are attached to kidneys by a double fold of peritoneum as

Options

A. Pericardium
B. Mesorchium
C. Urinogenital duct
D. Vasa efferentia

Explanation

To answer the question, "In frogs, testes are attached to kidneys by a double fold of peritoneum as," we need to analyze the options provided and identify the correct term that describes the structure connecting the testes to the kidneys.

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking for the specific term that describes the double fold of peritoneum that connects the testes to the kidneys in frogs.

2. **Analyzing the Options**:
- **Pericardium**: This is a membrane that surrounds the heart. It is not related to the reproductive system or the connection between testes and kidneys.
- **Mesorchium**: This is a specific term that refers to the double fold of peritoneum that attaches the testes to the kidneys in frogs. This is a crucial term for our answer.
- **Urinogenital duct**: This refers to the duct that carries urine and reproductive fluids. In frogs, the ureters serve this function, but it does not describe the connection between the testes and kidneys.
- **Vasa afferentia**: These are the ducts that connect the testes to the kidneys, but they do not refer to the double fold of peritoneum.

3. **Identifying the Correct Answer**: Based on the analysis, the correct answer is **mesorchium**, as it specifically describes the structure that attaches the testes to the kidneys in frogs.

4. **Final Answer**: In frogs, testes are attached to kidneys by a double fold of peritoneum as **mesorchium**.