Longest bone of frog is

Options

A. humerus
B. femur
C. radio-ulna
D. tibio-fibula

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the longest bone in a frog. We need to identify which of the given options (femur, humerus, radioulna, tibiofibula) is the longest.

2. **Identifying Frog Characteristics**: Frogs belong to the class Amphibia and are part of the group Anura, which includes tailless amphibians like frogs and toads. They have adaptations for both aquatic and terrestrial habitats.

3. **Analyzing the Frog's Skeleton**: The skeletal system of frogs is relatively reduced, and they have a vertebral column that consists of only 10 vertebrae, including the urostyle.

4. **Examining the Limbs**: Frogs have forelimbs and hind limbs. The forelimbs are not as strong as the hind limbs. The hind limbs are adapted for leaping, which is essential for their locomotion and catching prey.

5. **Identifying the Bones in the Hind Limb**: The hind limb consists of several bones:
- **Femur**: This is the thigh bone and is identified as the longest bone in the hind limb.
- **Tibia and Fibula**: These are present but are shorter than the femur.
- **Tarsals**: The ankle bones, which are seven in number.
- **Metatarsals**: Five in number.
- **Phalanges**: Also known as digits, there are 14 in total.

6. **Conclusion**: Based on the analysis, the longest bone in the frog is the **femur**.

### Final Answer:
The longest bone of the frog is the **femur**.

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