The kidney of an adult frog is

Options

A. Metanephros
B. Opisthonephros
C. Pronephros
D. Mesonephros

Answer

To determine the type of kidney present in an adult frog, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Kidneys**: Familiarize yourself with the four types of kidneys: Metanephros, Opistonephros, Pro-nephros, and Mesonephros. Each type has distinct characteristics and functions.

2. **Identify the Functional Unit**: Recognize that the functional unit of the kidney is the nephron. Nephrons are responsible for filtering blood, reabsorbing necessary substances, and secreting waste products.

3. **Examine the Function of Nephrons**: In adult frogs, the nephrons filter the initial urine from the blood, reabsorb water and nutrients, and secrete waste to produce the final urine.

4. **Determine the Kidney Type in Frogs**: Based on the functions of the nephrons and the structure of the kidneys in adult frogs, it is established that they possess metanephric kidneys.

5. **Conclude the Answer**: Since the adult frog has metanephric kidneys, we can conclude that the correct answer to the question is Metanephros.

### Final Answer:
The kidney of an adult frog is **Metanephros**.