In which of the following organisms fertilization is internal but development of zygote occurs outside the body of female?

Options

A. Frog
B. Bony fishes
C. Birds
D. Dog dish

Answer

To solve the question, "In which of the following organisms fertilization is internal but development of zygote occurs outside the body of female?", we will analyze each option provided to determine the correct answer.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Internal Fertilization**: This occurs when the male and female gametes fuse inside the female's body.
- **External Development**: This refers to the process where the zygote develops outside the female's body.

2. **Analyzing the Options**:
- **Option 1: Frog**:
- Frogs exhibit **external fertilization**. The male and female frogs release their gametes into the water, where fertilization occurs. Therefore, this option is excluded.

- **Option 2: Bony Fishes**:
- Similar to frogs, bony fishes also exhibit **external fertilization**. The eggs and sperm are released into the water, and fertilization occurs outside the female's body. Thus, this option is also excluded.

- **Option 3: Birds**:
- In birds, **fertilization is internal**. The male's sperm fertilizes the female's egg inside her body. After fertilization, the female lays the fertilized egg, and the development of the zygote occurs outside her body in the egg. This option fits the criteria of the question.

- **Option 4: Dogfish**:
- Dogfish (a type of shark) exhibit **internal fertilization** as well. The male dogfish uses a clasper to insert sperm into the female, and the development of the zygote also occurs internally. Therefore, this option is incorrect.

3. **Conclusion**:
- Based on the analysis, the only organism where fertilization is internal and development of the zygote occurs outside the body of the female is **birds**. Thus, the correct answer is **Option 3: Birds**.